Gas treating device and gas treating method

ABSTRACT

A gas processing apparatus  1  includes a processing container  2  for applying a processing to a wafer W while using a processing gas, a mount table  5  arranged in the processing container  2  to mount the wafer W, a shower head  22  arranged corresponding to the wafer W on the mount table  5  to discharge the processing gas into the processing container  2  and exhausting means  132  for exhausting the interior of the processing container  2 . The shower head  22  has first gas discharging holes  46  arranged corresponding to the wafer W mounted on the mount table  5  and second gas discharging holes  47  arranged around the first gas discharging holes  46  independently to discharge the processing gas to the peripheral part of the wafer W. Thus, with a uniform gas supply to a substrate, it is possible to perform a uniform gas processing.

TECHNICAL FIELD

The present invention relates to a gas processing apparatus and a gasprocessing method for performing a gas processing of a substrate to beprocessed by use of a processing gas.

BACKGROUND OF ART

In the semiconductor manufacturing process, metal, for example, W(tungsten), WSi (tungsten silicide), Ti (titanium), TiN (titaniumnitride), TiSi (titanium silicide), etc. or metallic compound thereof isdeposited to form a film in order to fill up contact holes formed on asemiconductor wafer as an object to be processed (referred “wafer”hereinafter) or wiring holes for connecting wires to each other.

As the film deposition for these elements, physical vapor deposition(PVD) technique has been employed conventionally. Recently, however,both of miniaturization and high integration of a device have beenparticularly required and therefore, its design rule becomes severe inparticular. Correspondingly, as both device's line-width and diameter ofholes become smaller with the progress of high aspect ratio, a “PVD”film has been getting incapacitated. Therefore, it has been recentlycarried out to form a film of such a metal or metal compounds bychemical vapor deposition (CVD) technique promising an ability offorming a film of better quality.

For example, by use of WF₆ (tungsten hexafluoride) gas as the processinggas and H₂-gas as the reduction gas, a W-film is produced due to areaction on a wafer represented by the formula of “WF₆+H₂→W+6HF”. TheCVD film deposition process like this is carried out by mounting a waferon a mount table in a processing container and further supplying thecontainer with WF₆-gas and H₂-gas discharged from a shower head as beinga gas discharging mechanism arranged in a position opposing the waferwhile exhausting the interior of the processing container, therebyforming a designated “processing-gas” atmosphere in the processingcontainer.

Under the process like this, however, as a reduction gas having a highdiffusion velocity, e.g. H₁-gas, quickly diffuses in the processingcontainer throughout and is discharged therefrom, the concentration ofthe reduction gas is easy to drop around the peripheral part of a wafer.Particularly, since the film deposition apparatus has been large-sizedcorresponding to a recent large-sized wafer from 200 mm to 300 mm insize, the above reduction in the concentration of the reduction gas inthe periphery of the wafer becomes remarkable to cause a film depositionrate to be lowered in the same area. Consequently, the uniformity infilm thickness is lowered remarkably.

Meanwhile, when forming a W-film on SiO₂ or Si, it is performed inadvance of the deposition of W-film to cover the SiO₂ or Si with thinand uniform Ti-film, TiN-film or their lamination film as the barrierlayer in view of improvement in adhesive property between a W-film andthe SiO₂ or Si, restriction of a reaction of W with Si etc. Inconnection, when filling in recesses or the like, hydrogen gasexhibiting reduction property less than that of silane gas(Si_(n)H_(2m+n), SiH_(n)Cl_(4−n)) is mainly used in order to make itsembedding property excellent. Then, there is a possibility that the“under” barrier layer is attacked by non-reacted WF₆-gas, so that thebarrier layer reacts with fluorine to expand its volume therebyproducing a projecting defect called “volcano” and further, there is anoccasion that voids occur in holes to be embedded. In order to preventthe occurrence of such defects, it is attempted to firstly form anucleate W-film (nucleation film) by a minimal thickness in the orderfrom 30 to 50 nm with by the use of silane gas having more intensivereduction power in place of hydrogen gas and subsequently, to form amain W-film with the nucleation film as the starting point by the use ofH₂-gas and WF₆-gas. However, in spite of the adoption of such a method,the step coverage of a nucleation film is deteriorated due tocontamination etc. on the surface of a barrier layer as the under layer,so that the fill-in property of the main W-film gets worse. Thistendency becomes remarkable with the progress of miniaturization insemiconductor devices.

In order to solve such a problem, it is also attempted, in advance ofthe formation of the nucleation film, to perform an initiation processto allow the under barrier layer to absorb SiH_(X) (X<4) with the supplyof only silane gas for a predetermined period and subsequently, to makea growth of the nucleation film with the so-absorbed barrier layer asthe starting point. However, this measure is believed to beinsufficient.

Therefore, we and applicant previously proposed a technique to form aninitial W-film on the surface of a substrate to be processed (JapanesePatent Application No. 2001-246089). According to the technique, thereare repeatedly performed a reduction-gas supply process of supplying thereduction gas and a W-gas supply process of supplying a W-content gaswith the interposition of a purging process of evacuating whilesupplying an inert gas between the above processes. With this technique,it is possible to form a uniform nucleation film in even a minute hole,with high step coverage, whereby the above problem can be solved.

Nevertheless, if the above technique is applied to a normal W-filmdeposition apparatus, then WF₆-gas reacts to silane gas in a shower headas a gas discharging mechanism, so that a W-film is formed in the showerhead, thereby decreasing the reproducibility among the surfaces ofwafers. In order to avoid an occurrence of such a problem, it isnecessary to lower a temperature of a gas discharging part of the showerhead less than 30° C. However, since the shower head is generally cooleddown from its lateral surface, it is difficult to attain the temperatureof a central part of the shower head less than 30° C. by means ofgenerally cooling water. In the present circumstances where the showerhead is also large-sized because of large-sized wafers, the requirementof attaining the temperature of the central part of the shower head lessthan 30° C. would require an ultra cold chiller to cause a greatincrease in the installation cost of a system due to countermeasures ofdew condensation etc.

In the CVD film deposition apparatus of this kind, meanwhile, if forminga W-film on a substrate having an exposed TiN-film, then a compound“TiN” is etched by fluorine during the film depositing operation, sothat reaction by-product materials, such as titanium fluoride (TiF_(x)),stick to the shower head and the inner wall of the chamber andthereafter, the by-product materials are peeled off to be the origin ofparticles. Therefore, after completing a designated film deposition, itis carried out to introduce ClF₃-gas (as a cleaning gas) into a chamberthrough a shower head thereby cleaning the apparatus. Regarding thiscleaning, since the cleaning efficiency is increased with elevatedtemperature, there is performed a “flashing” process to introduceClF₃-gas into the chamber while heating the shower head at predeterminedintervals by a heater embedded in the shower head.

However, due to the shower head being large-sized for large wafers thatrequires for the heater to have a high-power output, heat from theshower head to a container lid is also heat transferred, so that theheater is required to have more power to compensate such a dissipativeheat. The requirement makes it difficult to elevate the temperature ofthe shower head up to a predetermined temperature.

Additionally, with an apparatus being large-sized, if heating the showerhead by the heater, then the shower head has a thermal expansion of theorder of 1 mm, so that a problem of heat distortion about the showerhead arises.

Under such a situation, an object of the present invention is to providea gas processing apparatus and a gas processing method by which it ispossible to avoid defects about a gas discharging mechanism, the defectsbeing accompanied with the apparatus being large-sized.

More in detail, an object of the invention is to provide a gasprocessing apparatus and a gas processing method that can perform auniform gas processing by supplying a substrate with gas uniformly.Additionally, an object of the invention is to provide a gas processingapparatus that allows a gas discharging mechanism to be heated with highefficiency. Further, an object of the invention is to provide a gasprocessing apparatus that can reduce an influence of thermal expansionwhen the gas discharging mechanism is heated. Still further, in case ofan apparatus that alternately supplies two processing gases required tokeep a temperature of the gas discharging mechanism low, an object ofthe invention is to provide the gas processing apparatus that can coolthe whole gas discharging mechanism to a desired temperature withoutusing any special installation, such as ultra cold chiller, despite thatthe gas discharging mechanism is large-sized.

Further, in case of supplying two processing gases alternately to form afilm, an object of the invention is to provide a gas processingapparatus and a gas processing method that can prevent formation of anunnecessary film in the gas discharging mechanism without coolingspecially.

DISCLOSURE OF THE INVENTION

In order to solve the above-mentioned problems, according to the firstaspect of the present invention, there is provided a gas processingapparatus comprising: a processing container for accommodating asubstrate to be processed; a mount table arranged in the processingcontainer to mount the substrate; a processing-gas discharging mechanismarranged in a position opposing the substrate to be processed mounted onthe mount table to discharge a processing gas into the processingcontainer; and exhausting means for exhausting an interior of theprocessing container, wherein the processing-gas discharging mechanismincludes; a first gas discharging part provided corresponding to thesubstrate to be processed mounted in the mount table and a second gasdischarging part arranged around the first gas discharging partindependently to discharge the processing gas into the periphery of thesubstrate to be processed mounted on the mount table.

In the second aspect of the present invention, there is provided a gasprocessing apparatus for applying a gas processing to a substrate to beprocessed while using a first processing gas of a relatively highdiffusion velocity and a second processing gas of a relatively lowdiffusion velocity, the gas processing apparatus comprising; aprocessing container for accommodating a substrate to be processed; amount table arranged in the processing container to mount the substrateto be processed thereon; a processing-gas discharging mechanism arrangedin a position opposing the substrate to be processed mounted on themount table to discharge a gas containing the first processing gas andthe second processing gas into the processing container; and exhaustingmeans for exhausting an interior of the processing container, whereinthe processing-gas discharging mechanism includes; a first gasdischarging part provided corresponding to the substrate to be processedmounted in the mount table to discharge the gas containing the firstprocessing gas and the second processing gas and a second gasdischarging part arranged around the first gas discharging partindependently, to discharge the first processing gas into the peripheryof the substrate to be processed mounted on the mount table.

In the third aspect of the present invention, there is provided a gasprocessing apparatus comprising; a processing container foraccommodating a substrate to be processed; a mount table arranged in theprocessing container to mount the substrate to be processed thereon; aprocessing-gas discharging mechanism arranged in a position opposing thesubstrate to be processed mounted on the mount table to discharge aprocessing gas containing H₂-gas and WF₆-gas into the processingcontainer; and exhausting means for exhausting an interior of theprocessing container, wherein the processing-gas discharging mechanismincludes; a first gas discharging part provided corresponding to thesubstrate to be processed mounted in the mount table to discharge theprocessing gas containing H₂-gas and WF₆-gas and a second gasdischarging part arranged around the first gas discharging partindependently, to discharge H₂-gas into the periphery of the substrateto be mounted on the mount table.

In the fourth aspect of the present invention, there is provided a gasprocessing method for applying a gas processing to a substrate to beprocessed in a processing container while supplying a processing gas tothe substrate, the gas processing method comprising the steps of:discharging the processing gas through a first gas discharging partprovided so as to oppose the substrate to be processed; and dischargingthe processing gas to the periphery of the substrate to be processedthrough a second gas discharging part provided around the first gasdischarging part independently, thereby performing the gas processing.

In the fifth aspect of the present invention, there is provided a gasprocessing method for applying a gas processing to a substrate to beprocessed while supplying the substrate in a processing container with afirst processing gas of a relatively high diffusion velocity and asecond processing gas of a relatively low diffusion velocity, the gasprocessing method comprising the steps of; discharging a gas containingthe first processing gas and the second processing gas from a first gasdischarging part that is arranged so as to oppose the substrate to beprocessed; and farther discharging the first processing gas from asecond gas discharging part that is arranged around the first gasdischarging part independently, thereby performing the gas processing.

In the sixth aspect of the present invention, there is provided a gasprocessing method for applying a gas processing to form a W-film on asubstrate to be processed while supplying the substrate to be processedin a processing container with a processing gas containing H₂-gas andWF₆-gas, the gas processing method comprising the steps of: discharginga processing gas containing H₂-gas and WF₆-gas from a first gasdischarging part that is arranged so as to oppose the substrate to beprocessed, and discharging H₂-gas from a second gas discharging partthat is arranged around the first gas discharging part independently,thereby forming the W-film on the substrate to be processed.

According to the first aspect and the fourth aspect of the presentinvention, by discharging the processing gas through the first gasdischarging part and further discharging the processing gas from thesecond gas discharging part, which is arranged around the first gasdischarging part independently, into the periphery of the substrate tobe processed, it is possible to prevent the concentration of theprocessing gas from being lowered in the periphery of the substrate tobe processed, whereby an in-plane uniform gas processing can be appliedto the substrate to be processed.

Again, according to the second aspect and the fifth aspect of thepresent invention, by discharging a mixing gas of the first and secondprocessing gases through the first gas discharging part and furtherdischarging the first processing gas from the second gas dischargingpart, which is arranged around the first gas discharging partindependently, into the periphery of the substrate to be processed, itis possible to prevent the concentration of the first processing gas,which is easy to diffuse due to its relatively high diffusion velocity,from being lowered in the periphery of the substrate to be processed,whereby the in-plane uniform gas processing can be applied to thesubstrate to be processed.

Further, according to the third aspect and the sixth aspect of thepresent invention, by discharging the processing gas containing H₂-gasand WF₆-gas through the first gas discharging part and furtherdischarging H₂-gas from the second gas discharging part, which isarranged around the first gas discharging part independently, into theperiphery of the substrate to be processed, it is possible to preventthe concentration of H₂-gas, which is easy to diffuse due to itsrelatively high diffusion velocity, from being lowered in the peripheryof the substrate to be processed, whereby the in-plane uniform gasprocessing can be applied to the substrate to be processed.

In common with the above gas processing apparatuses, the gas dischargingmechanism may include a gas discharging plate having the first gasdischarging part and the second gas discharging part, while each of thefirst gas discharging part and the second discharging part may have aplurality of gas discharging holes formed in the gas discharging plate.Then, the gas discharging mechanism may be constructed to have a coolantpassage. Further, it is preferable that the coolant passage is arrangedin an area of the gas discharging plate where the gas discharging holesare formed. The coolant passage is formed so as to correspond to theshape of a gas discharging plate's part interposed among the plural gasdischarging holes in the gas discharging plate's area where the gasdischarging holes are formed. For example, the coolant passage is formedconcentrically. Further, the gas discharging mechanism may have aheater.

Again, it is preferable that the plural gas discharging holes includedin the second gas discharging part are arranged outside the periphery ofthe substrate to be processed on the mount table. Further, it is alsopreferable that the plural gas discharging holes included in the secondgas discharging part are arranged perpendicularly to the substrate to beprocessed on the mount table. With the arrangement mentioned above, itis possible to prevent the concentration of the first processing gasfrom being lowered in the periphery of the substrate to be processed. Inthe second gas discharging part as above, the plural gas dischargingholes may be arranged in the periphery of the first gas dischargingpart, in one or more lines. Alternatively, the plural gas dischargingholes may form a first line and a second line, both of which areconcentric to each other, in the periphery of the first gas dischargingpart and the gas discharging holes forming the first line and the gasdischarging holes forming the second line may be arranged alternately.

Further, it is preferable that the above gas processing apparatuscomprises a coolant passage arranged in the processing-gas dischargingmechanism; a coolant flow piping arranged both in front of the coolantpassage and in the rear; a bypass piping connected, both in front of theprocessing-gas discharging mechanism and in the rear, to the coolantflow piping while bypassing the processing-gas discharging mechanism; apressure relief valve arranged on the downstream side of the coolantpassage in the coolant flow piping; a valves defining a flowing pathwayof the coolant; control means for controlling the valves; and a heaterfor heating the processing-gas discharging mechanism, wherein whencooling the processing-gas discharging mechanism, the control meanscontrols the valves so as to allow the coolant to flow into the coolantpassage, when heating the processing-gas discharging mechanism, thecontrol means operates the heater and further controls the valves so asto stop the inflow of the coolant into the coolant passage and allow thecoolant to flow into the bypass piping, and when lowering a temperatureof the processing-gas discharging mechanism in its elevated condition intemperature, the control means controls the valves so as to allow thecoolant to flow into both of the coolant passage and the bypass piping.Consequently, it is possible to attain rapid ascent and descent intemperature of the gas discharging mechanism.

Moreover, in any one of the above-mentioned gas processing apparatuses,it is preferable that the exhausting means carries out exhaust from theperipheral side of the substrate to be processed on the mount table. Inthis case, preferably, the gas processing apparatus further comprises anannular baffle plate having a plurality of exhaust holes, wherein theexhausting means exhausts the interior of the processing containerthrough the exhaust holes. Furthermore, in any one of theabove-mentioned gas processing methods, it is preferable to carry outexhaust from the peripheral side of the substrate to be processed, atthe gas processing.

In the seventh aspect of the present invention, there is provided a gasprocessing apparatus comprising: a processing container foraccommodating a substrate to be processed; a mount table arranged in theprocessing container to mount the substrate to be processed thereon; aprocessing-gas discharging mechanism arranged in a position opposing thesubstrate to be processed mounted on the mount table to discharge aprocessing gas into the processing container; and exhausting means forexhausting an interior of the processing container, wherein theprocessing-gas discharging mechanism includes a gas discharging parthaving a discharging hole for discharging the processing gas; a basepart supporting the gas discharging part, a heater provided in the gasdischarging part; and a gap layer defined between the gas dischargingpart and the base part.

With the above-mentioned constitution, since the gap layer formedbetween the gas discharging part and the base part functions as a heatinsulating layer to suppress heat dispersion from the heater of the gasdischarging part, it is possible to uniformly heat the gas dischargingpart with high efficiency. Then, it is likely that the gas leaks outfrom the gas discharging mechanism through the gap layer. In order toprevent such a leakage, however, a seal ring etc. may be interposedbetween the gas discharging part and the base part.

In the eighth aspect of the present invention, there is provided a gasprocessing apparatus comprising: a processing container foraccommodating a substrate to be processed; a mount table arranged in theprocessing container to mount the substrate to be processed thereon; aprocessing-gas discharging mechanism arranged in a position opposing thesubstrate to be processed mounted on the mount table to discharge aprocessing gas into the processing container; and exhausting means forexhausting an interior of the processing container, wherein theprocessing-gas discharging mechanism includes a gas discharging parthaving a discharging hole for discharging the processing gas; a basepart supporting the gas discharging part; a heater provided in the gasdischarging part; and a fastening mechanism for fastening the gasdischarging part to the base part so as to allow a relative displacementtherebetween.

In this way, as the gas discharging part is fastened to the base part soas to allow a relative displacement therebetween, even if the gasdischarging part is heated by the heater and expanded thermally, thereis produced almost no strain in the gas discharging part and also in thebase part due to the relative displacement between the gas dischargingpart and the base part, whereby it is possible to reduce the influenceof thermal expansion on the gas discharging part.

In the ninth aspect of the present invention, there is provided a gasprocessing apparatus comprising: a processing container foraccommodating a substrate to be processed; a mount table arranged in theprocessing container to mount the substrate to be processed thereon;first processing-gas supplying means for supplying a first processinggas into the processing container; second processing-gas supplying meansfor supplying a second processing gas into the processing container; aprocessing-gas discharging mechanism arranged in a position opposing thesubstrate to be processed mounted on the mount table to discharge thefirst processing gas and the second processing gas supplied from thefirst and second processing-gas supplying means respectively, into theprocessing container; and exhausting means for exhausting an interior ofthe processing container, the gas processing apparatus supplying thefirst processing gas and the second processing gas alternately to reactthese gases on the substrate to be processed thereby forming adesignated film thereon, wherein the processing-gas dischargingmechanism includes a gas discharging plate having a plurality of gasdischarging holes for discharging the first and second processing gasesand a coolant passage, and the coolant passage is arranged in a gasdischarging plate's area where the gas discharging holes are formed.

According to the constitution mentioned above, in the apparatus tosupply the first processing gas and the second processing gas, which arerequired to keep the temperature of the gas discharging part of the gasdischarging mechanism low, the coolant passage is arranged in the gasdischarging plate's area where the gas discharging holes are formed.Therefore, even if the gas discharging mechanism is large-sized with thelarge-sized substrate to be processed, it becomes possible toeffectively cool the gas discharging part to a desired temperaturewithout using any special installation, such as ultra cold chiller andwith a normal coolant, such as cooling water.

In this case, the coolant passage is formed so as to correspond to theshape of a gas discharging plate's part interposed among the plural gasdischarging holes in the gas discharging plate's area where the gasdischarging holes are formed. For instance, the coolant passage isformed concentrically, for example, as a groove. The processing-gasdischarging mechanism may be provided with a heater.

In the gas processing apparatus of the ninth aspect, it is preferablethat the apparatus further comprises: a coolant flow piping arrangedboth in front of the coolant passage and in the rear; a bypass pipingconnected, both in front of the processing-gas discharging mechanism andin the rear, to the coolant flow piping while bypassing theprocessing-gas discharging mechanism; a pressure relief valve arrangedon the downstream side of the coolant passage in the coolant flowpiping; a group of valves defining a flowing pathway of the coolant;control means for controlling the group of valves; and a heater forheating the processing-gas discharging mechanism, wherein when coolingthe processing-gas discharging mechanism, the control means controls thegroup of valves so as to allow the coolant to flow into the coolantpassage, when heating the processing-gas discharging mechanism, thecontrol means operates the heater and further controls the group ofvalves so as to stop the inflow of the coolant into the coolant passageand allow the coolant to flow into the bypass piping, and when loweringa temperature of the processing-gas discharging mechanism in itselevated condition in temperature, the control means controls the groupof valves so as to allow the coolant to flow into both of the coolantpassage and the bypass piping.

In the tenth aspect of the present invention, there is provided a gasprocessing method for alternately supplying a first processing gas and asecond processing gas to a substrate to be processed in a processingcontainer with through a gas discharging member to allow these gases toreact on the substrate to be processed thereby forming a designated filmthereon, the gas processing method comprising the step of supplying thefirst processing gas and the second processing gas into the processingcontainer through gas supply pathways separated from each other in thegas discharging member.

In the eleventh aspect of the present invention, there is provided a gasprocessing apparatus comprising: a processing container foraccommodating a substrate to be processed; a mount table arranged in theprocessing container to mount the substrate to be processed thereon;first processing-gas supplying means for supplying a first processinggas into the processing container; second processing-gas supplying meansfor supplying a second processing gas into the processing container; aprocessing-gas discharging mechanism arranged in a position opposing thesubstrate to be processed mounted on the mount table to discharge thefirst processing gas and the second processing gas supplied from thefirst and second processing-gas supplying means respectively, into theprocessing container; and exhausting means for exhausting an interior ofthe processing container, the gas processing apparatus supplying thefirst processing gas and the second processing gas alternately to reactthese gases on the substrate to be processed thereby forming adesignated film thereon, wherein the processing-gas dischargingmechanism includes a first gas supply pathway and a second gas supplypathway separated from each other, and the first processing gas and thesecond processing gas are discharged through the first gas supplypathway and the second gas supply route, respectively and individually.

According to the tenth and the eleventh aspects, when alternatelysupplying the first processing gas and the second processing gas inorder to form a film, the processing container is supplied with thefirst processing gas and the second processing gas through the gassupply pathways separated from each other in the gas discharging member.Therefore, in the gas discharging member, the first processing gas doesnot come into contact with the second processing gas, so that it becomespossible to prevent deposition of undesired film in the gas dischargingmember without any special cooling.

In the tenth aspect, it is preferable to interpose a purging step ofpurging the interior of the processing container between the supply ofthe first processing gas and the supply of the second processing gas.

In the eleventh aspect, it is preferable that the gas processingapparatus further comprises purge means for purging the interior of theprocessing container between the supply of the first processing gas andthe supply of the second processing gas. Again, the processing-gasdischarging mechanism may be constructed so that it has a gasdischarging plate, a plurality of first gas discharging holes succeedingto the first gas supply pathway are arranged at the central part of thegas discharging plate part, and that a plurality of second gasdischarging holes succeeding to the second gas supply pathway arearranged at the peripheral part of the gas discharging plate. Further,the gas discharging member may be provided, on its under surfacealternately, with a plurality of first gas discharging holes succeedingto the first gas supply pathway and a plurality of second gasdischarging holes succeeding to the second gas supply pathway. Moreover,the gas discharging mechanism is preferable to have a coolant passageformed in an area of the gas discharging plate where the gas dischargingholes are formed. The coolant passage is formed so as to correspond tothe shape of a gas discharging plate's part interposed among the pluralgas discharging holes in the gas discharging plate's area where the gasdischarging holes are formed. For instance, the coolant passage isformed concentrically. The processing-gas discharging mechanism may beprovided with a heater. Further, it is preferable that the gasprocessing apparatus further comprises: a coolant flow piping arrangedboth in upstream of the coolant passage and in the downstream; a bypasspiping connected, both in upstream of the processing-gas dischargingmechanism and in the downstream, to the coolant flow piping whilebypassing the processing-gas discharging mechanism; a pressure reliefvalve arranged on the downstream side of the coolant passage in thecoolant flow piping; a group of valves defining a flowing pathway of thecoolant; control means for controlling the group of valves; and a heaterfor heating the processing-gas discharging mechanism, wherein whencooling the processing-gas discharging mechanism, the control meanscontrols the group of valves so as to allow the coolant to flow into thecoolant passage, when heating the processing-gas discharging mechanism,the control means operates the heater and further controls the group ofvalves so as to stop the inflow of the coolant into the coolant passageand allow the coolant to flow into the bypass piping, and when loweringa temperature of the processing-gas discharging mechanism in itselevated condition in temperature, the control means controls the valvesso as to allow the coolant to flow into both of the coolant passage andthe bypass piping.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front view of a CVD film deposition apparatus in accordancewith the first embodiment of the present invention.

FIG. 1B is a side view of the CVD film deposition apparatus inaccordance with the first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a main body of the CVD filmdeposition apparatus of FIGS. 1A and 1B.

FIG. 3 is a sectional view taken along a line A-A of the apparatus ofFIG. 2.

FIG. 4 is a sectional view taken along a line B-B of the apparatus ofFIG. 2.

FIG. 5 is a sectional view showing a joint part between a shower plateand a shower base in the CVD film deposition apparatus in accordancewith the first embodiment of the present invention, in enlargement.

FIG. 6 is a view showing a top surface of the shower plate 35 in the CVDfilm deposition apparatus in accordance with the first embodiment of thepresent invention.

FIG. 7 is a sectional view showing the peripheral part of a lower partof the shower head in the apparatus of FIG. 2, in enlargement.

FIG. 8 is a sectional view showing the vicinity of the peripheral partof the lower part of the shower head in enlargement, in case ofarranging the second gas discharging holes doubly.

FIG. 9A is a view showing one example of the arrangement of the secondgas discharging holes in enlargement, in case of arranging the secondgas discharging holes doubly.

FIG. 9B is a view showing another example of the arrangement of thesecond gas discharging holes in enlargement, in case of arranging thesecond gas discharging holes doubly.

FIG. 10 is a sectional view showing the vicinity of the peripheral partof the lower part of the shower head in enlargement, in case ofarranging the second gas discharging holes obliquely.

FIG. 11 is a sectional view showing the vicinity of the peripheral partof the lower part of the shower head in enlargement, in case ofarranging the second gas discharging holes inside the outer periphery ofa wafer W obliquely.

FIG. 12 is a sectional plan view showing the other structure of theshower head.

FIG. 13 is a perspective view showing an interior structure of a casingof a gas introducing part of FIG. 2, in its exploded state.

FIG. 14 is a sectional view taken along a line C-C of the apparatus ofFIG. 3.

FIG. 15 is a sectional view taken along a line D-D of the apparatus ofFIG. 3.

FIG. 16 is a back view showing the opening-and-closing conditions of alid body in the CVD film deposition apparatus shown in FIGS. 1A and 1B.

FIG. 17 is a circuit diagram for explanation of a cooling control systemused in the CVD film deposition apparatus in accordance with the firstembodiment.

FIG. 18 is a graph where its horizontal axis represents the flow rate ofH₂-gas, while the vertical axis represents the uniformity of W-film.

FIG. 19 is a graph showing the distribution of film thickness, which isobtained by measuring the thickness of W-film at respective measuringpoints 1 to 161 established along the diameter of a wafer W on filmdeposition as a result of changing the supply rate of H₂-gas toperipheral H₂-gas discharging holes variously and of which horizontalaxis represents the measuring points, while the vertical axis representsthe thickness of W-film at the respective measuring points.

FIG. 20 is a view in cooling a shower head by using the conventionalcoolant passage, showing the relationship between the diametric positionof a shower plate and its temperature at respective temperatures ofcooling water.

FIG. 21 is a vertical sectional view showing a shower head part of themain body of a CVD apparatus in accordance with the second embodiment ofthe present invention.

FIG. 22 is a horizontal sectional view taken along a line E-E of FIG.21, showing the shower head part of the main body of the CVD apparatusin accordance with the second embodiment of the present invention.

FIG. 23A is a sectional view showing the structure of a first circularpassage in the shower head of FIG. 21.

FIG. 23B is a sectional view showing the structure of a third circularpassage in the shower head of FIG. 21.

FIG. 24 is a sectional view showing the structure of a semiconductorwafer on which a W-film is formed by the apparatus in accordance withthe second embodiment of the present invention.

FIG. 25 is a view for explanatory of an example of W-film formation flowcarried out by the apparatus in accordance with the second embodiment ofthe present invention.

FIG. 26 is a sectional view showing a condition where an initial W-filmis formed on a under barrier layer of the semiconductor wafer of FIG.24.

FIG. 27 is a view showing a calculation example of the cooling conditionof a shower plate of the apparatus in accordance with the secondembodiment of the present invention.

FIG. 28 is a sectional view showing a condition where a main W-film isformed on the initial W-film on the under barrier layer of thesemiconductor wafer of FIG. 26.

FIG. 29 is a sectional view showing a condition where a reactiveintermediate represented by SiH_(x) is formed by the application of aninitiation processing on the under barrier layer of the semiconductorwafer of FIG. 26.

FIG. 30 is a sectional view showing a condition where a passivationW-film is formed on the first W-film of FIG. 26.

FIG. 31 is a sectional view showing another example of the coolantpassage applied to the second embodiment of the present invention.

FIG. 32 is a sectional view showing a CVD apparatus in accordance withthe third embodiment of the present invention.

FIG. 33A is a pattern diagram for explanation of the gas-flow in aSiH₄-gas supply process when forming a first W-film by using theapparatus of the third embodiment of the present invention.

FIG. 33B is a pattern diagram for explanation of the gas-flow in aWF₆-gas supply process when forming a first W-film by using theapparatus of the third embodiment of the present invention.

FIG. 34 is a schematic sectional view showing another example of theshower head of the third embodiment of the present invention.

FIG. 35 is a horizontal sectional view taken along a line F-F of FIG.34.

PREFERRED EMBODIMENTS FOR EMBODYING THE INVENTION

Referring to the attached drawings, embodiments of the present inventionwill be described in detail, below.

FIG. 1A is a front view of a CVD film deposition apparatus in accordancewith the first embodiment of the present invention. Further, FIG. 1B isa side view of the same apparatus. Still further, FIG. 2 is a schematicsectional view of the CVD film deposition apparatus, FIG. 3 a sectionalview taken along a line A-A of FIG. 2, and FIG. 4 is a sectional viewtaken along a line B-B of FIG. 2. This CVD film deposition apparatus isprovided to form a tungsten (W) film on a semiconductor wafer W (simplyreferred “wafer W” below) as a substrate to be processed, with the usedof H₂-gas and WF₆-gas.

As shown in FIGS. 1A and 1B, this CVD film deposition apparatus has amain body 1. Under the main body 1, there is a lamp unit 85. On the topof the main body 1, a lid 3 supporting a shower head 22 described lateris provided to be openable and closable. Further above the lid, upperexhaust pipes 128 a, 128 b are arranged so as to communicate withexhaust passages 121, 122 mentioned later, respectively. Again, belowthe main body 1, there is provided a lower exhaust pipe 131 that isconnected to the main body 1 through a confluence part 129interconnecting the upper exhaust pipes 128 a, 128 b connected theretoand an exhaust passage 130 mentioned later. This lower exhaust pipe 131is arranged at the left corner of the front part of the main body 1 andalso in a position to withdraw from the lamp unit 85.

As shown in FIG. 2, the main body 1 has a processing container 2 shapedto be a bottomed cylinder and made of e.g. aluminum etc. In theprocessing container 2, a cylindrical shield base 8 is provided to standfrom the bottom of the processing container 2. Arranged on an opening inthe upper part of the shield base 8 is an annular base ring 7 thatsupports an annular attachment 6 on the inner peripheral side of thering 7. Being supported by gibbosity parts (not shown) projecting intothe inner peripheral edge of the attachment 6, a mount table 5 isarranged to mount the wafer W thereon. A later-mentioned baffle plate 9is arranged outside the shield base 8. Further, the afore-mentioned lid3 is arranged on an opening in the upper part of the processingcontainer 2, while a later-mentioned shower head 2 is arranged in aposition opposing to the wafer W mounted on the mount table 5.

In a space surrounded by the mount table 5, the attachment 6, the basering 7 and the shield base 8, a cylindrical reflector 4 is provided torise from the bottom of the processing container 2. This reflector 4 isprovided, in e.g. three locations, with slit parts (FIG. 2 shows onelocation). At positions corresponding to the slit parts, lift pins 12for lifting up the wafer W from the mount table 5 are arranged so as tobe movable up and down respectively. The lift pins 12 are supported by adrive rod 15 through an annular supporting member 13 and a joint 14outside the reflector 4. The drive rod 15 is connected to an actuator16. The lift pins 12 are formed by heat ray transmitting material, forexample, quartz. Further, supporting members 11 are provided integrallywith the lift pins 12. Penetrating the attachment 6, the supportingmembers 11 are adapted so as to support an annular clamp ring 10 abovethe attachment 6. The clamp ring 10 is formed by a cabonaceous componenteasy to absorb heat, such as amorphous carbon and SiC, or ceramics, suchas Al₂O₃, AlN and black-AlN.

With the above-mentioned constitution, when the actuator 16 makes thedrive rod 15 move up and down, both of the lift pins 12 and the clampring 10 move up and down integrally. When transferring the wafer W, thelift pins 12 and the clamp ring 10 are raised until the lift pins 12project from the mount table 4 by a predetermined length. When mountingthe wafer W carried on the lift pins 12 on the mount table 5, the liftpins 12 are withdrawn into the mount table 5, while the clamp ring 10 islowered to a position to abut on the wafer W and further hold it, asshown in FIG. 2.

Into the space surrounded by the mount table 5, the attachment 6, thebase ring 7 and the shield base 8, a purge gas from a purge-gas supplymechanism 18 is supplied through a purge-gas passage 19 formed in thebottom part of the processing container 2 and flow channel 19 a that aredisposed the inside and lower part of the reflector 4 at lieu intervalto eight locations to communicate with the purge-gas passage 19. Byallowing the so-supplied purge gas to flow radially-outwardly through aclearance between the mount table 5 and the attachment 6, a processinggas from the later-mentioned shower head 22 is prevented from invadingto the backside of the mount table 5.

Additionally, the shield base 8 is provided, at several positionsthereof, with openings 20. A plurality of pressure regulating mechanisms21 are arranged on the inner peripheral side of the openings 20. When apressure difference between an inside of the shield base 8 and theoutside exceeds a predetermined value, the pressure regulatingmechanisms 21 are activated to communicate the inside of the shield base8 with the outside. Consequently, it is possible to prevent the clampring 10 from fluttering due to excessive pressure difference between theinside of the shield base 8 and outside and also possible to prevent anymember into the container from being broken by an excessive force.

In the bottom part of the processing container 2 right under the mounttable 5, an opening 2 a is defined while the periphery is beingsurrounded by the reflector 4. A transmitting window 17 made of heat raymaterial, such as quartz, is fitted to the opening 2 a in an airtightmanner. The transmitting window 17 is held by a not-shown holder. Asapphire coating is applied on the surface of the transmitting window17. The above lamp unit 85 is arranged below the transmitting window 17.The lamp unit 85 includes a heating chamber 90, a rotating table 87 inthe heating chamber 90, lamps 86 attached to the rotating table 87 and arotating motor 89 arranged in the bottom of the heating chamber 90 torotate the rotating table 87 through a rotating shaft 88. Further, thelamps 86 are respectively provided with reflecting parts for reflectingtheir heat rays and also arranged so that the heat rays radiated fromthe respective lamps 86 uniformly reach the under surface of the mounttable 5 directly or indirectly upon reflection of the inner periphery ofthe reflector 4. As this lamp unit 85 allows the lamps 86 to radiate theheat rays while making the rotating motor 89 rotate the rotating table87, the beat rays emitted from the lamps 86 illuminates the undersurface of the mount table 5 through the transmitting window 17, so thatthe mount table 5 is heated by the heat rays uniformly.

The shower head 22 includes a cylindrical shower base 39 formed so as tofit its outer periphery to the upper part of the lid 3, a plate shapedintroducing plate 29 fitted to the upper part of the shower base 39 onits inner circumferential side and a shower plate 35 attached to thelower part of the shower base 39. The introducing plate 29 is provided,on its top, with a gas introducing part 23 mentioned later. A spacerring 40 is arranged on the outer periphery of the shower plate 40.

The introducing plate 29 is formed, at its center, with a first gaspassage 30 for passage of a main gas. In the plate 29, a plurality ofsecond gas passages 44A, for example, five passages (see FIG. 13, onlyone shown in FIG. 2) are formed so as to surround the first gas passage30, for passage of a peripheral H₂-gas. Besides, regarding the number ofthe second gas passages 44, any number will do so long as they can makea uniform flow of the peripheral H₂-gas.

An annular coolant passage 36 is formed in the peripheral portion of theupper part of the shower plate 35. This coolant passage 36 is suppliedwith cooling water as the coolant through a coolant supply path 37 a,while the cooling water is discharged through a coolant discharging path37 b. In this way, the cooling water as the coolant is circulated.Consequently, at the film deposition, it is possible to cool the showerplate 35 to a predetermined temperature, for example, the order of 35°C., thereby suppressing the reaction of SiH₄-gas on the surface of theshower head 22. Note, a cooling control system employed at this coolingwill be described later. Additionally, an annular heater 38 is embeddedin the under side of the shower plate 35. This heater 38 is suppliedwith electricity from a heater power source 138. During the cleaningoperation, if heating the shower plate 35 up to a predeterminedtemperature, for example, more than 160° C. by the heater 38, then it ispossible to etch ClF₃ at a great etching rate. On the outer periphery ofthe shower plate 35, a spacer ring 40 is arranged in order to bill a gapbetween the shower plate 35 and a sidewall of the processing container2.

As shown in FIG. 5, a clearance (vacancy layer) 135 functioning as aheat insulating layer is defined between the shower plate 35 and theshower base 39. If such a clearance 135 is not provided, then heat ofthe heater 38 is transmitted to shower base 39 directly and theso-transmitted heat is easy to dissipated outside through theintermediary of the lid 3. In such a case, it will be required that theheater 35 has a great output. Especially, in an apparatus for processinga wafer of 300 mm in diameter, the shower head 22 will be large-sizedremarkably. Then, under such a dispersion of heat, it becomessubstantially impossible to heat the shower plate 35 to 160° C. or more,uniformly. To the contrary, according to the embodiment since theclearance 135 operates as an thermal insulation layer, it is possible toreduce such a heat dispersion remarkably, allowing the temperature ofthe shower plate 35 to be elevated to 160° C. or more uniformly. A sealring 136 is interposed between the shower plate 35 and the shower base39 and also in their inner circumferential portions, in order to preventa leakage of gas flowing from the shower head 22 to the outside via theclearance 135.

FIG. 6 is a view showing the top surface of the shower plate 35. Asshown in this figure, on one side of the periphery of the shower plate35, there are collectively arranged a coolant passage 37 for coolingwafer or the like, a thermocouple inserting part 141 and a heaterterminal part 142. Thus, this side of the periphery of the shower plate35 provides a fixing part 144 fixed to the shower base 39 through fourbolts 143. In this fixing part 144, the coolant passage 37, thethermocouple inserting part 141 and the heater terminal part 142 arerespectively sealed up so as not to be a leakage of the cooling wateretc. The other side of the shower plate 35 provides a moving part 146fastened to the shower base 39 by a bolt 145 so as to allow a relativedisplacement between the shower plate 35 and the shower base 39. In thismoving part 146, as shown in FIG. 5, the diameter of a bolt insertinghole 147 is larger than the diameter of the bolt 145 by the order of 2mm. A Teflon washer 148 is interposed between the bolt 145 and theshower plate 35. Consequently, when the shower plate 35 is heated to itsthermal expansion by the heater 38 during the cleaning operation, it ispossible to attain a positive slipping between the bolt 145 and theTeflon washer 148. In case of a film deposition apparatus for a wafer of300 mm in diameter, if the shower base 35 at 35° C. during the filmdeposition is heated up to the order of 160° C., then a thermalexpansion of the shower plate 35 is on the order of 1 mm. Therefore, ifthe shower plate 35 is fixed to the shower base 39 completely, there isarises a strain between the shower plate 35 and the shower base 39,which causes various problems, for example, leakage of gas, shortage inlife span of the apparatus, etc. While, by establishing a plate's part,which is not inconvenient for movement of the shower plate 35, as themoving part 146 capable of moving the shower base 39, it is possible toavert the negative impact derived from the thermal expansion of theshower plate 35. Additionally, owing to the interposition of the Teflonwasher 148, a positive slippage arises between the bolt 145 and theshower plate 35. As a result, frictional wear is avoided between theshower plate 35 and the shower base 39 thereby producing no particlearound them.

In a space in the shower head 22, which is surrounded by the shower base39, the gas introducing plate 29 and the shower plate 35, there is agenerally-circular horizontal partition 31 that is arranged just belowthe gas introducing plate 29 horizontally. In the inner circumferentialpart of the horizontal partition 31, a cylindrical gibbosity part 31 ais formed so as to project upwardly. This cylindrical gibbosity part 31a is connected to the gas introducing plate 29.

On the other hand, a current plate 33 is arranged in the space in theshower head 22 while positioning its plate's surface horizontally. Thecurrent plate 33 is formed with a plurality of gas pass holes 34 andarranged at a predetermined distance from the shower plate 35 through acylindrical spacer 33 a. Further, a vertical partition 32 in the form ofa cylinder is arranged between the outer periphery of the horizontalpartition 31 and the spacer 33 a.

Therefore, the inside space of the shower head 22 contains a spatialpart 22 a between the horizontal partition 31 and the current plate 33,a spatial part 22 b between the shower base 39 and the verticalpartition 32 and also the spacer 33 a, a spatial part 22 c between thegas introducing plate 29 and the horizontal partition 31 and a spatialpart 22 d between the current plate 33 and the shower plate 35. Amongthese parts, the spatial part 22 b is communicated with the spatial part22 c through a clearance 45 formed between the horizontal partition 31and the shower base 39. The first gas introducing hole 30 of the gasintroducing plate 29 is communicated with the spatial part 22 a, whilethe second gas introducing hole 44 is communicated with the spatial part22 c. However, the spatial part 22 c is secluded from the spatial part22 a by the horizontal partition 31 and the gibbosity part 31 a. Again,the spatial part 22 b is secluded from the spatial part 22 a by thevertical partition 32, while the spatial part 22 b is secluded from thespatial part 22 d by the spacer 33 a. Noted, the current plate 33 may beformed integrally with the vertical partition 32.

At the center part of the shower plate 35, that is, in the plate'sportion in the spatial part 22 d, a plurality of first gas dischargingholes 46 are formed to communicate with the spatial part 22 d. At theouter peripheral part of the shower plate 35, that is, in the plate'sportion facing onto the annular spatial part 22 b, second gasdischarging holes 47 for discharging the peripheral H₂-gas are formed soas to communicate with the spatial part 22 b, circumferentially. Note,the first gas discharging holes 46 are arranged, for example, in alattice pattern or radially. For example, the diameter of the first gasdischarging hole 46 ranges from 0.1 to 5 mm, preferably, 1 to 3 mm. Thesecond gas discharging hole 47 has a diameter similar to that of thefirst gas discharging hole. Besides, the diameter of the second gasdischarging hole 47 may be larger or smaller than that of the first gasdischarging hole 46.

FIG. 7 is a partial enlarged view of the lower part of the shower head22 in the embodiment, showing the currents of gases discharged from thefirst gas discharging holes 46 for discharging the main gas and thesecond gas discharging holes 47 for discharging the peripheral H₂-gas,in the form of arrows. As shown in FIG. 7, the main gas supplied fromthe first gas passage 30 flows from the spatial part 22 a into thespatial part 22 d through the gas passing holes 34 in the current plate33 and subsequently, the main gas is discharged from the spatial part 22d to the wafer W vertically, through the first gas discharging holes 46in the shower plate 35. While, H₂-gas from the second gas passage 44flows from the spatial part 22 c into the second spatial part 22 bthrough the clearance 45 and subsequently, the H₂-gas is discharged fromthe second spatial part 22 d to the outside portion (i.e. the side ofthe clamp ring) of wafer W vertically, through the second gasdischarging holes 47 in the shower plate 35. The H₂-gas may bedischarged to the peripheral part of the wafer W.

However, unlimitedly to only the arrangement of FIG. 7, the second gasdischarging holes 47 may be arranged in a pattern to arrange themoutside the outer peripheral margin of the wafer W in two linesconcentrically, for example, as shown in FIG. 8. Alternatively, they maybe arranged in three or more lines. Further, the second gas dischargingholes 47 may be formed above the outer periphery of the wafer W in oneline or outside the outer periphery of the wafer W in two or more lines.In case of the second gas discharging holes 47 in two or more lines, asshown in FIG. 9A, they may be arranged so that the second gasdischarging holes 47 in adjacent lines 47 a, 47 b overlap each other. Oragain, as shown in FIG. 9B, the second gas discharging holes 47 formingthe adjacent lines 47 a, 47 b may be arranged alternately. Note, thealternate arrangement allows gas to be supplied more uniformly. In thealternate arrangement, as shown in FIG. 9B, it is desirable to arrangeeach of the second gas discharging holes 47 forming one line 47 a in aposition apart from two adjoining holes of the second gas dischargingholes 47 forming the other line 47 b by equal distances d. Additionally,as shown in FIG. 10, the second gas discharging holes 47 may be formedobliquely to the outer peripheral margin of the wafer W from its outsideto the inside within the range of 0 to 45 degrees. Then, the diameter ofthe second gas discharging hole 47 ranges from 0.1 to 3 mm, preferably,0.1 to 1.5 mm. Regarding the oblique arrangement of the second gasdischarging holes 47, the discharge positions of the second gasdischarging holes 47 are not limited to respective position outside theperiphery of the wafer W only, as shown in FIG. 10. So long as thedischarge positions are included in a range to allow formation of auniform film, the discharge positions of the second gas dischargingholes 47 may be respective position inside the periphery of the wafer W,as shown in FIG. 11.

As mentioned above, the heater 38 is embedded in the shower plate 35, sothat it is heated by the heater 38. In view of further preventingdispersion of heat due to heat transmission in heating the shower plate35, as shown in FIG. 12, it is preferable to interpose a resinous sealring 48 of heat-resistant resin, e.g. fluorocarbon resin between thespacer 33 a of the current plate 11 and the shower plate 35, therebyaccomplishing heat insulation.

Next, the aforementioned gas introducing part 23 will be described indetail.

The gas introducing part 23 includes a current plate 28 fitted to thetop of the introducing plate 29, a lower plate 27, an intermediate plate26 and an upper plate 25, all of which are stacked in order andaccommodated in a casing 24. The casing 24 is provided, in its upperpart, with a gas introductory port 42 connected to a later-mentioned gassupply mechanism 50 to introduce the peripheral H₂-gas and gasintroducing ports 41, 43 for introducing the main gas.

FIG. 13 is a perspective view showing the interior structure of thecasing 24 in the above-mentioned gas introducing part 23. The upperplate 25 is provided with a cavity 103 communicating with the gasintroducing port 42 of the casing 24, a passage 101 communicating withthe gas introducing port 41 of the casing 24 and a passage 102communicating with the gas introducing port 43 of the casing 24. On thebottom surface of the cavity 103, gas passage holes 104 for flow of theperipheral H₂-gas are formed at five locations in the circumference ofthe cavity 103. Through a groove 105 formed in the intermediate plate26, the passage 101 in communication with the gas introductory port 41is communicated with a vertical bore 106 formed in the intermediateplate 26 and the lower plate 27 successively. The passage 102 incommunication with the gas introducing port 43 is communicated with thevertical bore 106 through a passage 108 formed in the intermediate plate26 and a groove 109 formed in the lower plate 27. The vertical bore 106is communicated with the first gas passage 30 at the center of theintroducing plate 29 through current holes 111 of the current plate 28.With the constitution mentioned above, H₂-gas, WF₆-gas, etc. are mixedtogether in the vertical bore 106, so that the resulting mixed gas issupplied from the main gas passage 30. While, the gas passage holes 104for flow of the peripheral H₂-gas are respectively communicated with gaspassages 44 formed at five positions in the introducing plate 29 so asto surround the first gas passage 30, through a passage 107 in theintermediate plate 26 and another passage 110 in the lower plate 27.

In the above gas introducing part 23, gases supplied to the gasintroducing ports 41, 43 are mixed together in the vertical bore 106 andsuccessively supplied into the shower head 33 through the first gaspassage 30. The peripheral H₂-gas supplied to the gas introducing port42 is dispersed from the cavity 105 into five gas passage holes 104 andsuccessively supplied into the shower head 22 through the second gaspassage 44. Then, the gas supplied into the first gas passage 30 flowsfrom the spatial part 22 a in the shower head 33 to the spatial part 22d through the main-gas passing holes 34 of the current plate 33. In thespatial part 22 d, the gas is diffused and further expired toward thewafer W through the main-gas discharge holes 46 uniformly. While, theperipheral H₂-gas supplied into the second gas passage 44 flows frontthe spatial part 22 c in the shower head 33 to the spatial part 22 bthrough the clearance 45 in the circumference of the plate-shapedpartition 31. In the spatial part 22 b, the gas is diffused and furtherexpired toward the wafer W through the second gas discharge holes 47uniformly. In this way, since the first gas discharge holes 46 and thesecond gas discharge holes 47 are supplied with gases respectively, itis possible to discharge different gases of different compositionsthrough these discharge holes.

Next, the gas supply mechanism 50 will be described.

The gas supply mechanism 50 includes a ClF₃-gas supply source 51 forsupplying ClF₃-gas as the cleaning gas, a WF₆-gas supply source 52 forsupplying WF₆-gas as the W-content gas, an Ar-gas supply source 53, aH₁-gas supply source 54 for supplying H₂-gas as the reduction gas, aN₂-gas supply source 55 and a SiH₄-gas supply source 56 for supplyingSiH₄-gas as the reduction gas.

A gas line 61 is connected to the C₁F₃-gas supply source 51, a gas line62 being connected to the WF₆-gas supply source 52, and a gas line 63 isconnected to the Ar-gas supply source 53. These gas lines 61, 62 and 63are connected to the gas introducing port 43 of the gas introducing part23. Both of gas lines 64, 65 are connected to the H₂-gas supply source54. In these gas lines 64 and 65, the gas line 64 is connected to thegas introducing port 42, while the gas line 65 is connected to the gasintroductory port 41 of the gas introducing part 23. A gas line 66 isconnected to the N₂-gas supply source 55, while a gas line 67 isconnected to the SiH₄-gas supply source 56. These gas lines 66 and 67are connected to the gas introducing port 41 of the gas introductorypart 23. In these gas lines 61, 62, 63, 64, 65, 66 and 67, there areprovided a mass-flow controller 70 and closing valves 71, 72 in frontand behind, for each line. Note, in the gas supply mechanism 50, the gassupply using the valves etc. is controlled by a control unit 80.

While, as shown in FIGS. 3 and 4, there is attached, between the shieldbase 8 and the sidewall of the processing container 8, the circularshaped baffle plate 9 that is provided, on its whole periphery, withexhaust holes 9 a, as mentioned before. An annular exhaust space 127 isformed below this baffle plate 9. As shown in FIG. 4, below the baffleplate 9, exhaust spaces 123, 124 are arranged in positions formingopposing corners of the processing container 2. Arranged near an exhaustinlet of the exhaust space 123 is a bottom partition wall 125 that has acircular arc-shaped section, allowing the gas to be discharged throughgaps between both ends of the partition wall 125 and the sidewall of theprocessing container 2. Further arranged near an exhaust inlet of theexhaust space 124 is a bottom partition wall 126 that has a circulararc-shaped section similarly, allowing the gas to be discharged throughgaps between both ends of the partition wall 126 and the sidewall of theprocessing container 2.

Next, a structure for exhausting the exhaust spaces 123, 124 will bedescribed with reference to FIGS. 14 and 15. FIG. 14 is a sectional viewtaken along a line C-C of FIG. 3, while FIG. 15 is a sectional viewtaken along a line D-D of FIG. 3. As shown in FIG. 14, theabove-mentioned exhaust space 124 is communicated with one end of theexhaust passage 122 formed in the sidewall of the processing container 2and the lid 3, while the other end of the exhaust passage 122 isconnected to the upper exhaust pipe 128 b.

As shown in FIG. 15, the upper exhaust pipe 128 b is interconnected, atthe other corner of the processing container 2, with a confluence part129. This confluence part 129 is connected to the upper end of exhaustpassage 130 that penetrates the lid 2 and the sidewall of the processingcontainer 2. The lower end of the exhaust passage 130 is connected to anexhausting mechanism 132 through the lower exhaust pipe 131. Note,although FIG. 14 shows the structure in the vicinity of the exhaustspace 124, the vicinity of the exhaust space 123 is provided with thesimilar structure. As shown in FIGS. 1A and 1B, two upper exhaust pipes128 a, 128 b connected to two points at the diagonal positions of theprocessing container 2 are interconnected, at the other corner of theprocessing container 2, to the confluence part 129 and further join toone exhaust passage 130 through the confluence part 129. The exhaustpassage 130 is further connected to the exhaust mechanism 132 throughone lower exhaust pipe 131 below the processing container 2. Then, byoperating the exhaust mechanism 132, the atmosphere in the processingcontainer 2 is discharged from the exhaust holes 9 a in the baffle plate9 into the annular exhaust space 127 below the plate 9 and discharge theexhaust spaces 123, 124 through the passage between both ends of thebottom partition wall 125 and the sidewall surface of the processingcontainer 2 and the passage between both ends of the bottom partitionwall 126 and the sidewall surface of the processing container 2. Then,the atmosphere is discharged upward through the exhaust passages 121,122 and further discharged downward from the upper exhaust pipe 128through the exhaust passage 130. In this way, by discharging theatmosphere in the processing container 2, it becomes possible todepressurize the interior of the processing container 2 to a designatedvacuum.

At this time, since the atmosphere flowing from the exhaust holes 9 a ofthe baffle plate 9 into the underside annular exhaust space 127 flows asshown with arrow of FIG. 4 while making a detour to avoid the bottompartition walls 125, 126, the atmosphere flowing out of the exhaustholes 9 a in the vicinity of the exhaust spaces 123, 124 is preventedfrom being discharged directly, allowing the atmosphere to be dischargedfrom the respective exhaust holes 9 a approximately uniformly.Accordingly, the atmosphere in the processing container 2 is exhaustedfrom the outer periphery of the mount table 5 uniformly. Additionally,according to the above constitution, since the interior of theprocessing container 2 can be exhausted through the single lower exhaustpipe 131 arranged in a position to avoid the lamp unit 85 at the lowerpart of the processing container 2, it is possible to simplify thestructure of the lower part of the processing container 2. Therefore, itis possible to attempt the miniaturization of the CVD film depositionapparatus and also possible to carry out maintenance of the apparatus,for example, exchange of the lamps 86 in the lamp unit 85 arranged belowthe processing container 2, with ease.

Next, a supporting mechanism in opening and closing the lid 3 of thisCVD film deposition apparatus will be described with reference to FIG.16. FIG. 16 is a back view of the CVD film deposition apparatus. Asshown in FIG. 16, the shower head 22 is attached to the center of thelid 3. Because of a considerable weight of the shower head 22, asupporting mechanism 150 is provided on the lateral side of the lid 3.The supporting mechanism 150 includes an arm 154 which is attached to arotating shaft 151 for rotating the lid 3 as shown with an imaginaryline of FIG. 16 so as to oppose the lid 3 and a rod member 153 havingits one end engaged with a shaft 152 on the arm 154, which has a maximumlength at positions shown with a solid line and an imaginary line ofFIG. 16 and which is expandable within a range shorter than the maximumlength. When closing the lid 3, the rod member 153 and the arm 154 arepositioned on the right side of the lid 3 as shown with the solid lineof FIG. 16. From this state, when rotating the lid 3 as shown with theimaginary line of FIG. 16, the rotating shaft 151 and the arm 154 incooperation with the rotation rotate in the clockwise directionintegrally, so that the rod member 153 expands and contracts whilefollowing the arm 154. As shown with the imaginary line of FIG. 16, whenthe lid 3 rotates with an angle of 180 degrees, the arm 154 rotates upto a position where the rod member 153 on the left side of the rid 3 hasthe maximum length. At the position, the rotations of the rotating shaft151 and the arm 154 are locked up by the rod member 153, so that the lid3 is maintained in its opened state as a result of rotating with theangle of 180 degrees. Owing to the provision of the so-constructedsupporting mechanism 150 on the lateral side of the lid 3, it becomespossible to open and close the rid 3 equipped with the shower head 22 ofheavyweight with case, whereby the maintenance property of the CVD filmdeposition apparatus can be improved.

Next, the cooling control system used for the main body 1 of the CVDfilm deposition apparatus of this embodiment will be described withreference to FIG. 17. This cooling control system 160 includes a primarycoolant piping 161 for circulating a primary coolant, such as tap water(city water), a first secondary coolant piping 162 where a secondarycoolant having its temperature controlled as a result of beat exchangewith the primary coolant piping 161 does circulate and a secondsecondary coolant piping 163 which is diverged from the first primarycoolant piping 162 to allow the similar secondary coolant to circulate.The secondary coolant is stored in a secondary coolant tank 164 and theso-stored secondary coolant circulates the first secondary coolantpiping 162 and the second secondary coolant piping 163.

The secondary coolant circulating in the first secondary coolant piping162 flows through the shower head 22, the chamber 2 (chamber wall) andthe reflector 4 in order from the upstream side, while the same water inthe second secondary coolant piping 163 flows through a transmittingwindow holder 165 (not shown in FIG. 2) holding the transmitting window17, the lamp unit 85 and a chamber seal 166 (not shown in FIG. 2), suchas seal ring, for sealing up the chamber 2 in order from the upstreamside.

The primary coolant piping 161 includes a ball valve 167 on the inletside and a ball valve 167 on the outlet side. A solenoid valve 169 isarranged near the “inlet-side” ball valve 167 and on its downstreamside. Near the “outlet-side” ball valve 168 and on its upstream side,there are arranged a strainer 170, a needle valve 171 and a flow meter172 in order from the upstream side. Further, on the downstream side ofthe solenoid valve 169, a heat exchanger 173 is arranged to perform heatexchange between the primary coolant and the secondary coolant.

In a non-branching part of the first secondary coolant piping 162 and onthe upstream side of the secondary coolant tank 164, there are providedan air operation valve 174, a needle valve 175 and the above heatexchanger 173, in order from the upstream side. Further, a bypass piping176 for bypassing these elements is arranged in the non-diverging part.In the non-branching part of the first secondary coolant piping 162 andon the downstream side of the secondary coolant tank 164, there areprovided a ball valve 178, a pump 179 for circulating the secondarycoolant and a ball valve 180, in order from the upstream side. An airdraft piping 181 for the pump 179 is arranged on the downstream side ofthe pump 179. The air draft piping 181 is provided with a ball valve182.

Above the secondary cooling water tank 164, there are a heater 185 and acooling plate 186 where the primary coolant circulates. The secondarycoolant tank 164 is provided, in its upper part, with a control part 187where the first secondary coolant piping 162 is arranged. While, on thedownstream side of the pump 179 in the first secondary coolant piping162, a thermocouple 133 is arranged to detect a temperature of thesecondary coolant. Detection signals from the thermocouple 183 areinputted to a temperature controller 184. Controlling the output of theheater 185, the temperature controller 184 is adapted so as to controlthe temperature of the secondary coolant flowing through the controlpart 185 to a desired temperature due to the balance between heating bythe heater 185 and cooling by the cooling plate 186. Note, the secondarycoolant tank 164 is provided, in its bottom part, with a drain piping188 having a ball valve 189.

On the downstream side of the reflector 4 in the first secondary coolantpiping 162, there are arranged a strainer 190, a needle valve 191 and aflow meter 192, in order from the upstream side. Additionally, on thedownstream side of the chamber seal 166 in the second secondary coolantpiping, there are arranged a strainer 193, a needle valve 194 and a flowmeter 195, in order from the upstream side.

In the shower head 22, the first secondary coolant 162 is connected toboth inlet side and outlet side of the above-mentioned coolant passage36. The first secondary coolant piping 162 is provided, on the upstreamand downstream sides, with air operation valves 196, 197, respectively.A pressure gauge 198 is arranged between the air operation valve 196 ofthe first secondary coolant piping 162 and the shower head 22. Further,a bypass piping 199 for bypassing the shower head 22 is connected to apart of the first secondary coolant piping 162 on the upstream side ofthe air operation valve 196 and another part of the piping 162 on thedownstream side of the air operation valve 197. The bypass piping 199 isprovided, on its inlet side, with an air operation valve 200. A piping201 flowing the secondary coolant tank 164 is connected to a part of thefirst secondary coolant piping 162 between the shower head 22 and theair operation valve 197. The piping 201 is provided with a pressurerelief valve 202. Note, all of the above valves are controlled by avalve controller 203.

Next, the operation of the above-constructed CVD film depositionapparatus to form a W-film on the surface of a wafer W will bedescribed.

First, it is performed to open a not-shown gate valve on the sidewall ofthe processing container 2 and load a wafer W into the processingcontainer 2 by a transfer arm. Next, after raising the lift pins 12 soas to gibbosite from the mount table 5 by a predetermined length andfurther receiving the wafer W, it is performed to withdraw the transferarm from the processing container 2 and further close the gate valve.Next, it is performed to lower the lift pins 12 and the clamp ring 10and make the lift pins 12 go under the mount table 5 to mount the waferW thereon. Additionally, it is carried out to lower the clamp ring 10 toa position to abut on the wafer W and hold it. Further, the exhaustmechanism 132 is operated to depressurize the interior of the processingcontainer 2 into a high vacuum condition. Then, while rotating therotating table 87 by the rotating motor 89, it is performed to light onthe lamps 86 in the heating chamber 90 to radiate heat rays, therebyheating the wafer W for a predetermined temperature.

Next, in order to apply the initiation process on the wafer W, it isperformed to supply respective processing gases from the Ar-gas supplysource 53, the N₂-gas supply source 55 and the SiH₄-gas supply source 56of the gas supply mechanism 50 at respective flow rates. Further, thegas lines 64, 65 are supplied with H₂-gas from the H₂-gas supply source54, at respective designated flow rates. Consequently, the mixture gasof Ar-gas, N₂-gas, SiH₄-gas and H₂-gas is discharged from the first gasdischarging holes 46 of the shower head 22 toward the wafer W therebyallowing the wafer W to absorb Si. Therefore, at the next step, anucleation film is formed on the wafer effectively and uniformly. H₂-gasmay be expired from the second gas discharging holes 47 toward theperiphery of the wafer W. Further, by starting supply of purge gas fromthe purge-gas supply mechanism 18, it is performed to prevent theprocessing gas from making a warparound for the backside of the mounttable 5.

After the initiation processing, while maintaining the above flow ratesof the respective processing gases, it is performed to start the supplyof WF₆-gas from the WF₆-gas supply source 52 at a predetermined flowrate smaller than that in a main film deposition process mentionedlater, thereby adding WF₆-gas to the gas expired from the first gasdischarging holes 46. In this state, it is performed to proceed withreducing reaction of a SiH₄-gas shown in the following formula (1) for apredetermined period, thereby forming a nucleation film on the surfaceof the wafer W.2WF₆+3SiH₄→2W+3SiF₄+6H₂  (1)

Subsequently, it is performed to stop the respective supply of WF₆-gas,SiH₄-gas and H₂-gas from the second gas discharging holes 47 and alsoincrease the supply amounts of Ar-gas, N₂-gas and H₂-gas from the firstgas discharging holes 46 thereby purging the processing gas for formingthe nucleation film. Additionally, the exhaust amount of the exhaustmechanism 132 is lowered to enhance a pressure inside the processingcontainer 2 for the main film deposition process and the temperature ofthe wafer W is stabilized.

Next, it is performed to restart the supply of WF₆-gas and H₂-gas fromthe second gas discharging holes 47 and further reduce the supplyamounts of Ar-gas, N₂-gas and H₂-gas from the first gas dischargingholes 46. In this state, it is performed to proceed with the formationof W-film by the H₂-gas reducing reaction shown in the following formula(2) for a predetermined period, thereby performing the main filmdeposition process to form a W-film on the surface of the wafer W.WF₆+3H₂→W+6HF  (2)

After completing the main film deposition process, it is carried out tostop the supply of WF₆-gas and further depressurize the interior of theprocessing container 2 by the exhaust mechanism 132 quickly whilemaintaining the supply of Ar-gas, H₂-gas and N₂-gas, thereby purging theresidual processing gas on completion of the main film depositionprocess from the processing container 2. Next, while stopping all thesupply of gases, the depressurizing is maintained to form a high vacuumin the processing container 2. Thereafter, it is carried out to raisethe lift pins 12 and the clamp ring 10 in order to allow the lift pins12 to gibbosite from the mount table 5 thereby raising the wafer W up toa position to allow the transfer arm to receive the wafer W. Then, thegate valve is opened and the transfer arm insert into the processingcontainer 2 to receive the wafer W on the lift pins 12. Next, by thewithdrawal of the transfer arm front the processing container 2, thewafer W is discharged therefrom, so that the film deposition process iscompleted.

According to the process as above, by discharging H₂-gas from second gasdischarging holes 47 onto the peripheral side of the wafer W whiledischarging the mixture gas containing WF₆-gas and H₂-gas from the firstgas discharging holes 46 onto the central side of the wafer W in theinitiation process, the nucleation process and the main film depositionprocess, it is possible to prevent the concentration of H₂-gas frombeing lowered on the peripheral side of the wafer W, whereby the wafer Wcan be formed with a W-film being uniform in film thickness.

FIG. 18 is a graph showing an investigation result in the uniformity ofa W-film formed on the wafer W by changing the flow rate of H₂-gasexpired from the second gas discharging holes 47 within a range from 0to 135% of the flow rate of H₂-gas discharged from the first gasdischarging holes 46, in the main film deposition process of the aboveprocess. In the graph, a horizontal axis designates the flow rate ofH₂-gas discharged from the second gas discharging holes 47, while thevertical axis represents the uniformity of W-film. From FIG. 18, it willbe found that an effect to improve the uniformity of W-film becomesremarkable when establishing the flow rate of H₂-gas discharged from thesecond gas discharging holes 47 to be more than 50% of the flow rate ofH₂-gas discharged from the first gas discharging holes 46. The morepreferable flow rate of H₂-gas from the second gas discharging holes 47is more than 60% of the flow rate of H₂-gas expired from the first gasdischarging holes 46.

FIG. 19 is a graph showing the distribution of film thickness as aresult of measuring the thickness of W-films on the wafers W atrespective measuring points 1 to 161 established along the diameter ofthe wafers W having W-films formed by changing the flow rate of H₂-gasdischarged from the second gas discharging holes 47 within a range from0 to 134% of the flow rate of H₂-gas discharged from the first gasdischarging holes 46. In the graph, a horizontal axis designatesrespective measuring points, while the vertical axis represents the filmthickness of W-film at the respective measuring points. From FIG. 19, itis confirmed that when no H₂-gas is discharged from the second gasdischarging holes 47, the film thickness of W-film gets thin on theperiphery of the wafer W, so that the film deposition of uniform W-filmin film thickness cannot be accomplished and that when H₂-gas isdischarged from the second gas discharging holes 47, the film thicknessof W-film is prevented from getting thin on the periphery of the waferW. Further, as a result of examinating the quality of W-film formed onthe wafer W in ease case, it is confirmed that the most high quality ofW-film can be obtained when setting the flow rate of H₂-gas dischargedfrom the second gas discharging holes 47 to be 134% of the flow rate ofH₂-gas discharged from the first gas discharging holes 46.

In each of the cases of: providing, outside the outer margin of thewafer W, with the peripheral H₂-gas discharging holes 47 perpendicularlyin a line, as shown in FIG. 7 (referred “H1” below); providing, outsidethe outer margin of the wafer W, with the peripheral H₂-gas dischargingholes 47 perpendicularly in two lines, as shown in FIG. 8 (referred “H2”below); and providing, outside the outer margin of the wafer W, with theperipheral H₂-gas discharging holes 47 obliquely, as shown in FIG. 10(referred “H4” below), the film deposition of W-film was carried outwhile discharging H₂-gas from the second gas discharging holes 47.Further, for comparison, the film deposition of W-film was carried outin the similar process but discharging no H₂-gas from the second gasdischarging holes 47 (shown “conventional” below). As a result ofcomparing the uniformity of respective W-films obtained in the aboveway, it is confirmed that the case H1 exhibits the most high uniformity,the case “H₂” the second uniformity, the case “H4” the third uniformity,and the case “conventional” case exhibits the worst uniformity.Consequently, it is confirmed that it is desirable to arrange the secondgas discharging holes 47 outside the outer margin of the wafer Wperpendicularly.

After picking out the wafer W on completion of the film depositionprocess, it is carried out to supply ClF₃-gas into the processingcontainer 2 as occasion demands, for example, after processing at leastone wafer, thereby performing a cleaning operation to remove unnecessaryadhesive agents adhering to the interior of the processing container 2.Additionally, as occasion demands, for example, after the filmdeposition process of at least several lots is finished, a flashingprocess is carried out besides the normal cleaning. In the flashingprocess, while supplying ClF₃-gas into the processing container 2, theshower plate 35 is heated to a temperature more than 160° C. by theheater 38. As a result, the reactivity of reaction by-product materialscontaining TiF_(x) adhering to the shower head 22 with ClF₃-gas isenhanced to remove the by-product materials containing TiF_(x) with anincreased etching rate of the by-product materials. In connection, it isnoted that since the temperature of the shower head at the normalcleaning is less than e.g. 100° C., the reaction by-product materialscontaining TiF_(X) are not removed but deposited.

In this case, since the gap (vacancy layer) 135 functioning as a thermalinsulation layer is defined between the shower plate 35 and the showerbase 39, the heat of the heater 38 is difficult to be transmitted to theshower base 9 directly and dissipated through the lid 3. Accordingly,without excessive output of the heater 38, it is possible to heat theshower plate 35 up to a temperature more than 160° C., which is suitablefor cleaning.

The moving part 146 of the shower plate 35 is fastened to the showerbase 39 by the bolt 145 so as to allow the relative displacement betweenthe shower plate 35 and the shower base 39. That is, since the diameterof the bolt insertion hole 147 is larger than the diameter of the bolt145 by the order of 2 mm and the Teflon washer 148 is interposed betweenthe bolt 145 and the shower plate 35, when the shower plate 35 is heatedby the heater 38 and expanded thermally during the cleaning operation,it is possible to attain a positive slipping between the bolt 145 andthe Teflon washer 148. Therefore, for example, even when the shower base35 is heated from 35° C. during the film deposition process to approx.160° C. and expanded thermally by approx. 1 mm in the film depositionapparatus for wafers of 300 mm in diameter, it is possible to prevent anoccurrence of problems that would be caused if the shower plate 35 isfixed to the shower base 39 completely, for example, gas leakage due tostrains of the shower plate 35 and the shower base 39, shortage in lifespan of the apparatus, etc. Additionally, as the positive slippage isproduced between the bolt 145 and the shower plate 35 by the Teflonwasher 148, it is possible to avoid wear between the shower plate 35 andthe shower base 39, whereby almost no particle is produced. In thiscase, as the bolt 145, it is preferable to employ a shoulder bolt asshown in FIG. 5. Consequently, even if no management is applied to atightening torque of the bolt, a distance r of the gap 135 is severelyguaranteed to make a uniform tightening pressure between the showerplate 35 and the shower base 39 with no dispersion.

On the other hand, during the film deposition, the cooling controlsystem 160 cools respective members in the main body 1 of the CVD filmdeposition apparatus, as mentioned above. In the cooling operation, bycooling the shower head 22 in order to suppress the reaction of SiH₄ onthe surface of the shower head 22, the adhesion of product materials tothe shower head is prevented. Nevertheless, it is noted that reactionby-product materials containing TiF_(x) adheres to the shower head.Therefore, since there is a need for the heater 38 to rise thetemperature of the shower head 22 at cleaning, particularly at flashing,up to a high temperature of 160° C. at which the reaction by-productmaterials containing TiF_(x) are removed, the coolant passage 36coexists with the heater 38 in the shower head 22. In general, when acoolant passage coexists with a heater in the above way, both heatingand cooling are deteriorated in their efficiencies.

To the contrary, according to this embodiment, it is possible to cancelsuch a problem by allowing the valve controller 203 in the coolingcontrol system 160 of FIG. 17 to control various valves as follows.

First, during the film deposition process, the air operation valves 196and 197 are opened, while the air operation valve 200 is closed. In thisstate, it is performed to allow the secondary coolant to flow from thesecond secondary coolant piping 162 to the coolant passage 36 in theshower head 22.

When heating the shower head 22 for the flashing process succeeding tothe film deposition, the heater 38 is operated and the air operationvalves 196 and 197 are together closed to stop the inflow of thesecondary cooling water into the coolant passage 36 in the shower head22, while the air operation valve 200 is opened to allow the secondarycoolant to flow through the bypass piping 199. At this time, waterremained in the coolant passage 36 is boiled due to heating by theheater 38. Consequently, the pressure relief valve in the piping 201 iscracked, so that the water in the coolant passage 36 is forced to thesecondary coolant tank 164. Consequently, it is possible to force thewater in the coolant passage 36 quickly, allowing the heating to becarried out with high efficiency.

On the other hand, when lowering the temperature of the shower head 22that has been heated highly, the air operation valve 196 and 197 areopened while leaving the air operation valve 200 as it is opened. While,if the air operation valve 196 and 197 are opened after closing the airoperation valve 200, the secondary coolant is vaporized by the showerhead 22 of high temperature, so that only steam flows into the firstsecondary coolant piping 162 on the downstream side of the shower head22. In such a case, the flow meter 192 is inactivated to exhibit anerror. Additionally, due to the flowing of steam of high temperature, itbecomes difficult to use a Teflon (trade mark) tube that is being inheavy usage as this kind of piping normally. To the contrary, by thusleaving the air operation valve 200 as it is opened, the coolant thatflowed through the bypass piping 199 is mixed with the steam via theshower head 22. As a result, a coolant of approx. 60° C. flows into thefirst secondary coolant piping 162 on the downstream side of the showerhead 22, so that the above problem does not occur. After the pressure atthe pressure gauge 198 is stabilized, in other words, after the boilingis settled, the air operation valve 200 is closed to make the secondarycoolant flow into the cooling water passage 36 only. Consequently, thecoolant allows the shower head 22 to be lowered in temperatureeffectively. Note, a period until the boiling goes down is graspedpreviously and the valves are controlled by the valve controller 203 ona basis of the above information about the period.

Next, the second embodiment of the present invention will be described.

In this embodiment, we explain an apparatus that embodies theabove-mentioned technique (referred “Sequential Flow Deposition: SFD”below) of alternately performing a process of supplying SiH₄-gas as thereduction gas and a process of supplying WF₆-gas as the film depositiongas with the via of a purging process of evacuating while supplying aninert gas between the above processes, thereby forming an initial W-filmon the surface of a wafer W.

As mentioned above, although the terminology “SFD” means a techniqueallowing a uniform nucleation film to be formed in even a minute devicehole at high step coverage, the technique is by nature a technique ofmaking the nucleation excellent. Therefore, the element W is easy to beformed on the surface of the shower head. Further, since the processinggas is consumed by the shower head, the water-to-water reproducibilityis especially deteriorated and the film deposition rate is also lowered.

As one effective countermeasure to avoid such a problem about thetechnique “SFD”, it can be recommended to cool the shower head 22 to atemperature less than 30° C. However, when allowing the coolant to flowinto the coolant passage 36 in the sidewall of the shower plate 35 inthe previous embodiment of FIG. 2, the temperature of the shower plate35 is difficult to be lowered in the vicinity of the center of theshower plate 35. In case of an apparatus corresponding to wafers of 300mm, if it is intended to cool down the center of the shower plate 35 toa temperature of 30° C., then it has to produce the coolant of −15° C.,which requires an ultra cold chiller thereby to cause a great increasein the installation cost of a system due to countermeasures of dewcondensation etc. This embodiment is provided to solve such a problem.

FIG. 21 is a vertical sectional view showing a shower head part of themain body of a CVD apparatus in accordance with the second embodiment ofthe present invention. FIG. 22 is a horizontal sectional view takenalong a line E-E of FIG. 21. Basically, this apparatus is constructedsimilarly to the CVD apparatus in the first embodiment and differs fromit in the cooling structure only. Therefore, elements identical to thoseof FIG. 2 are indicated with the same reference numerals respectivelyand their descriptions are simplified.

As shown in these figures, a shower plate 35′ of this embodiment issimilar to the shower plate 35 of the previous embodiment with respectto the provision of the first and second gas discharging holes 46, 47.However, the shower plate 35′ differs from the shower plate 35 in ahas-hole formation area where the first and second gas discharging holes46, 47 are formed, in other words, the formation of a concentriccircle-shape coolant passage 210 in a under side area of the showerplate. The cooling water is supplied to the coolant passage 210 througha coolant supply path 211 extending from a not-shown piping vertically.

The first and second gas discharging holes 46, 47 are formed radiallyand a plate's part interposed between these discharging holes is in theform of a concentric circle-shape. Therefore, the coolant passage 210 isshaped concentrically corresponding to the shape of the plate's part.This coolant passage 210 includes a first circular passage 210 a on theinnermost side from the center of the shower plate 35′, a secondcircular passage 210 b arranged outside the passage 210 and a thirdcircular passage 210 c on the outermost side, which is arranged outsidethe second gas discharging holes 47. Further, there are horizontallyjuxtaposed a coolant introducing path 212 a for introducing a coolantfrom the coolant supply path 211 into the third circular passage 210 cand a cooling water discharging path 212 b for introducing a coolantfrom the third circular passage 210 c into a not-shown coolantdischarging path. On the other hand, two horizontal passages 213 a, 213b in parallel are formed so as to extend from the opposite side of thecoolant introducing/discharging side in the gas-hole formation area ofthe shower plate 35′ up to the second circular passage 210 b whiledirecting the center of the shower plate 35′. Two horizontal passages214 a, 214 b in parallel are formed so as to extend from respectivepositions deviated from the horizontal passages 213 a, 213 b of thesecond circular passage 210 b slightly up to the first circular passage210 a.

In the third circular passage 210 c, pins 215 and 216 are arrangedbetween the coolant introducing path 212 a and the coolant introducingpath 212 b and between the horizontal passage 213 a and the horizontalpassage 213 b, respectively. Also, in the second circular passage 210 b,pins 217 and 218 are arranged between the horizontal passage 213 a andthe horizontal passage 214 a and between the horizontal passage 213 band the horizontal passage 214 b, respectively. Further, in the firstcircular passage 21 a, a pin 219 is arranged between the horizontalpassage 214 a and the horizontal passage 214 b. Since these pins 215 to219 are arranged so as to fill the passages, the current of the coolantis determined by these pins. That is, the cooling water supplied fromthe coolant introducing path 212 a to the third circular passage reachesthe first circular passage 210 a through the horizontal passage 213 aand the horizontal passage 214 b and subsequently flows in the firstcircular passage 210 a. The coolant flowing in the first circularpassage 210 a reaches the second circular passage 210 b through thehorizontal passage 214 a and subsequently flows in the second circularpassage 210 b. The coolant flowing in the second circular passage 210 breaches the third circular passage 210 c through the horizontal passage213 b and is discharged from the coolant discharging path 212 b by wayof the third circular passage 210 c.

These passages are appropriately established corresponding to the sizeof the shower head 22 and the pitches of the gas discharging holes. Inthe shower head of this embodiment, for example, the first circularpassage 210 a has its center diameter of 72 mm, the second circularpassage 210 b has its center diameter of 216 mm, and the third circularpassage 210 c has its center diameter of 375.5 mm. Further, the crosssections of the first circular passage 210 a and the second circularpassage 210 b measure 3.3 mm in width and 6 mm in height, respectively.The cross section of the third circular passage 210 c measures 11.5 mmin width and 6 mm in height. Further, the cross sections of the coolantintroducing path 212 a and the coolant discharging path 212 b measure7.5 mm in diameter, respectively. The cross sections of the horizontalpassages 213 a, 213 b measure 4.5 mm in diameter, respectively. Thecross sections of the horizontal passages 214 a, 214 b measure 3.5 mm inwidth and 6 mm in height, respectively.

As shown in FIG. 23A, the first circular passage 210 a can be providedby the following steps of; firstly forming a ring-shaped groovecorresponding to the first circular passage 210 a in the shower plate35′ from the upside; secondly arranging a corresponding lid 220 in thegroove; and finally welding the lid 220 to the shower plate 35′. Thesecond circular passage 210 b and the horizontal passages 214 a, 214 bare formed in the same manner. As shown in FIG. 23B, the third circularpassage 210 c can be provided by the following steps of: firstly forminga annular groove corresponding to the third circular passage 210 c inthe shower plate 35′ from the downside; secondly mounting acorresponding lid 221 in the above groove; and finally welding the lid221 to the shower plate 35′. Further, the coolant introducing path 212a, the coolant discharging path 212 b and the horizontal passages 213 a,213 b are respectively provided by drilling the circumferential end ofthe shower plate 35′.

Next, the operation of this embodiment will be described.

First, it is performed to mount a wafer W on the mount table 5, assimilar to the first embodiment. After clamping the wafer W by the clampring 105, a high vacuum state is formed in the processing container 2and further, the wafer W is heated to a predetermined temperature by thelamps 86 in the heating chamber 90.

In this state, the film deposition of W-film is carried out. During thefilm deposition process in the processing container, it is performed tocontinuously supply Ar-gas as the carrier gas from the Ar-gas supplysource 53 at a predetermined flow rate and also performed to continuevacuuming by the exhaust unit. Note, as the carrier gas, Ar-gas may bereplaced by the other inert gas, such as N₂-gas and He-gas.

For instance, the W-film formation of this embodiment is applied to awafer having a film structure as shown in FIG. 24. That is, on aSi-substrate 231, there is arranged an interlayer insulation film 232having a contact hole 233 formed therein. A barrier layer 236 consistingof a Ti-film 234 and a TiN-film 235 is arranged on the interlayerinsulation film 232 and also in the contact hole 233 in the film 232.According to the embodiment, a W-film is formed on the above barrierlayer 236.

Then, the W-film formation process is carried out, for example, inaccordance with a flow of FIG. 25. That is, after performing an initialW-film forming process ST1 by the technique “SPD”, a main W-film formingprocess ST2 is carried out. In the initial W-film forming process ST1, aprocess of supplying SiH₄-gas as the reduction gas and a process ofsupplying WF₆-gas as the source gas are carried out alternately whileinterposing a purging process of discharging a residual gas. In detail,the SiH₄-gas supply process S1 is firstly performed and subsequently,the WF₆-gas supply process S2 is conducted via the purging process S3.These processes are repeated by several times. At the end of the initialW-film forming process ST1, both of the SiH₄-gas supply process S1 andthe purging process S₃ are carried out. By definition of a processranging from one SiH₄-gas supply process S1 till a step before a startof the next-coming SiH₄-gas supply process S1 as one cycle, three cyclesof processes are performed in this embodiment. Nevertheless, the numberof repetition is not limited in particular. Alternatively, the purgingprocess may be an operation not to make the carrier gas flowing but onlyperforming the evacuation by an exhaust unit. As occasion demands, sucha purging process may be eliminated.

In the initial W-film forming process ST1, the SiH₄-gas supply processS1 has supplying SiH₄-gas from the SiH₄-gas supply source 56 to the gasline 67, allowing SiH₄-gas to flow through the gas introducing port 41and the first gas passage 30 in order, and discharging SiH₄-gas from thefirst discharging holes 46 of the shower head 22. The WF₆-gas supplyprocess S2 has supplying WF₆-gas from the WF₆-gas supply source 52 tothe gas line 62, allowing WF₆-gas to flow through the gas introducingport 43 and the first gas passage 30 in order, and discharging WF₆-gasfrom the first discharging holes 46 of the shower head 22. The purgingprocess S3 between these processes has stopping the supply of SiH₄-gasand WF₆-gas, supplying Ar-gas from the Ar-gas supply source 53 to thegas line 63, allowing Ar-gas to flow through the gas introducing port 41and the first gas passage 30 in order while discharging SiH₄-gas andWF₆-gas by the exhaust unit, and discharging Ar-gas from the first gasdischarging holes 46.

In the initial W-film forming process ST1, both a period T1 of eachSiH₄-gas supply process S1 and another period T2 of each WF₆-gas supplyprocess S2 are respectively suitable to be from 1 to 30 seconds,preferably, 3 to 30 seconds. Further, a period T3 of each purgingprocess S3 is suitable to be from 0 to 30 sec., preferably, 0 to 10 sec.Additionally, in the initial W-film forming process ST1, the flow ratesof SiH₄-gas and WF₆-gas are established to be relatively small in orderto reduce respective partial pressures. In detail, the flow rate ofSiH₄-gas in each SiH₄-gas supply process S1 is desirable to be in arange from 0.01 to 1 L/min, more preferably, from 0.05 to 0.6 L/min. Theflow rate of Ar-gas is desirable to be in a range from 0.1 to 10 L/min,more preferably, from 0.5 to 6 L/min. The flow rate of WF₆-gas in eachWF₆-gas supply process S2 is desirable to be in a range from 0.001 to 1L/min, more preferably, from 0.01 to 0.6 L/min. Further, the flow rateof Ar-gas is desirable to be in a range from 0.1 to 10 L/min, morepreferably, from 0.5 to 6 L/min. The process pressure at this time isdesirable to be in a range from 133 to 26600 Pa, more preferably, from266 to 20000 Pa. As a preferable example, it can be recommended to carryout the SiH₄-gas supply process S1 under the following conditions of:flow ratio SiH₄/Ar=0.09/3.9 (L/min); time T1=5 sec; and processpressure=998 Pa, and the WF₆-gas supply process S2 under the followingconditions of: flow ratio WF₆/Ar=0.03/3.9 (L/min); time T2=5 sec.; andprocess pressure=998 Pa. The process temperature in this initial W-filmforming process ST1 is set to a low temperature, for example, in a rangefrom 200 to 500° C., preferably, 250 to 450° C. Further, in this initialW-film forming process ST1, it is desirable that the film thickness forone cycle is in a range from 0.1 to 5 nm, more preferably, from 0.3 to 2nm.

In this way, by performing the supply of SiH₄-gas and the supply ofWF₆-gas alternately and repeatedly, a SiH₄-gas reducing reaction shownin the following formula (1) is formed, so that an initial W-film 237functioning as the nucleation film is formed on a under barrier layer236 uniformly at a high step coverage, as shown in FIG. 26.2WF₆+3SiH₄→2W+3SiF₄+6H₂  (1)

Then, due to the alternate supply of both SiH₄-gas as the reduction gasand WF₆-gas as the W-containing gas, there is an anxiety that thesegases react with each other in the shower head 22 thereby forming a filmthereon. As mentioned above, however, since the concentric coolantpassage 210 is formed in the gas-hole formation area of the shower plate35′, the cooling efficiency of the shower head 22 is enhanced incomparison with the previous embodiment. Thus, as the shower plate 35′can be cooled, at even a central part thereof, to be less than 30° C.without using an ultra cold chiller but using coolant of normal citywater, it is possible to restrict such a reaction of gases effectively.For example, if the arrangement of a coolant passage and its dimensionsare those in the above-mentioned concrete example, the calculationvalues by use of the cooling water at 25° C. are as shown in FIG. 27.From the figure, it will be understood that the arrangement of thisembodiment enables any position of the shower plate 35′ to be cooledbelow 30° C.

In the initial W-film forming process ST1, if an exhaust pathway at theSiH₄-gas supply process S1 is in common with that at the WF₆-gas supplyprocess S2, a problem arises in that SiH₄-gas reacts with WF₆-gas in theexhaust pipe, so that a large volume of reaction product adhere to pipesand a trap, thereby causing an increase in the frequency of maintenance.In such a case, it has only to divide the piping system into twopipelines. In connection, on the provide of a valve and an exhaust unitin each pipeline, it has only to divide the piping system into onesystem for the SiH₄-gas supply process S1 and another system for theWF₆-gas supply process S2 by manipulating the valves. For instance, ithas only to divide the lower exhaust pipe 131 into two pipes and furtherprovide each pipe with a valve and an exhaust unit.

After the initial W-film forming process ST1, by way of the sequentpurging process S3, the main W-film forming process ST2 is performed byuse of WF₆-gas being a W-content gas as the source gas and H₂-gas as thereduction gas. Then, WF₆-gas flows from the WF₆-gas supply source 52 tothe gas introducing port 43 through the gas line 62 and reaches the gasintroducing part 23. Main H₂-gas flows from the H₂-gas supply source 54to the gas introducing port 41 through the gas line 65 and reaches thegas introducing part 23. Then, these gases are mixed in the gasintroducing part 23. Next, the resulting mixture gas is introduced fromthe first gas passage 30 into the spatial part 22 a of the shower head22. Further, passing through the gas pass holes 34 in the current plate33 and the spatial part 22, the mixture gas is discharged from the firstgas discharging holes 46 through the spatial part 22 d. While, theperipheral H₂-gas flows from the H₂-gas supply source 54 to the gasintroducing port 42 through the gas line 64 and reaches the gasintroducing part 23. Then, H₂-gas is introduced from the second gaspassage 44 into the spatial part 22 c of the shower head 22 anddischarged from the second gas discharging holes 47 through the spatialpart 22 b. Due to the peripheral H₂-gas, there is no possibility thatthe periphery of the wafer W is short of H₂-gas, whereby it is possibleto accomplish a uniform supply of gas. In this way, with the supply ofby WF₆-gas and H₂-gas, a H₂ reducing reaction shown in the followingformula (2) is produced on the wafer W, so that the initial W-film 237functioning as the nucleation film is formed on a main W-film 238, asshown in FIG. 28.WF₆+3H₂→W+6HF  (2)

A period of the main W-film forming process ST2 depends on a filmthickness of a W-film to be formed. In this process, it is carried outto increase both of the flow rate of WF₆-gas and the flow rate of H₂-gasrelatively and additionally, the pressure in the processing container 2and the process temperature are slightly increased to make the filmdeposition rate large. Concretely, in order to obtain a step coverageand a film deposition rate more than some degrees thereof while avoidingan occurrence of volcano, the flow rate of WF₆-gas is desirable to be ina range from 0.001 to 1 L/min, more preferably, from 0.01 to 0.6 L/min.Further, the flow rate of H₂-gas is desirable to be in a range from 0.1to 10 L/min, more preferably, from 0.5 to 6 L/min. The flow rate ofAr-gas is desirable to be in a range from 0.01 to 5 L/min, morepreferably, from 0.1 to 2 L/min. The flow rate of N₂-gas is desirable tobe in a range from 0.01 to 5 L/min, more preferably, from 0.1 to 2L/min. The process pressure at this time is desirable to be in a rangefrom 2660 to 26600 Pa. Further, the process temperature ranges from 300to 500° C., preferably, 350 to 450° C. Regarding the partial gaspressure of WF₆-gas, a partial gas pressure exceeding 53 Pa is desirableto raise the step coverage to some degree. While, in view of avoiding anoccurrence of volcano, a partial gas pressure less than 266 Pa isdesirable when the process pressure in the processing container is lessthan 5300 Pa. Additionally, in view of enhancing a step coverage to somedegree and also avoiding the occurrence of volcano, the gas ratio ofWF₆/H₂ is desirable to be in a range from 0.01 to 1, more preferably,from 0.1 to 0.5.

By performing the supply process of SiH₄-gas in place of the aboveinitial W-film forming process ST1, the product between partial gaspressure and supply period at the former process being larger than thatat the latter process, there is produced a condition similar to such acondition that the above initiation process is applied to the surface ofa wafer W. As a result, as shown in FIG. 29, a reactive intermediate 239of SiH_(x) adheres to the surface of the barrier layer 236 on the waferW. Accordingly, the adhesion of the reactive intermediate allows theabove initial W-film 237 to be formed thereon more appropriately withrespect to the uniformity in film thickness. Note, the barrier layer 236is produced by means of the technique “CVD” or “PVD”.

Additionally, by interposing a passivation W-film forming processbetween the initial W-film forming process ST1 and the main W-filmforming process ST1, a passivation film 240 is deposited on the initialW-film 237, as shown in FIG. 30. Due to a passivation function that thispassivation film possesses, the damage on the Ti-film caused by thediffusion attack of the element F of WF₆ in forming the main W-film 238is prevented to make it possible to improve the embeddingcharacteristics furthermore. Although the passivation W-film formingprocess employs the same gas as that in the main W-film forming processST2, it is established that the flow ratio of WF₆-gas becomes smallerthan that in the main W-film forming process ST2.

After completing the main W-film forming process ST2, it is carried outto stop the supply of WF₆-gas and further depressurize the interior ofthe processing container 2 by a not-shown exhaust unit quickly whilemaintaining the supply of Ar-gas and H₂-gas, thereby purging theresidual processing gas remained as a result of completing the main filmforming process, from the processing container 2. Next, while stoppingall the supply of gases, the above depressurizing operation ismaintained to form a high vacuum in the processing container 2.Thereafter, it is carried out to raise the lift pins 12 and the clampring 10 thereby raising the wafer W up to a position where the transferarm receives the wafer W on the lift pins 12. Further, the transfer armtakes the wafer W out of the processing container 2, whereby the filmdeposition operation is ended. After taking out the wafer W, as occasiondemands, the interior of the processing container 2 is cleaned byfeeding ClF₃-gas from the ClF₃-gas source 61 into the processingcontainer 2. Further, if necessary, the above-mentioned flashing processmay be performed.

It is noted that, unlimitedly to three paths only, the number of thecoolant passages may be more or less than three. Since the is formedcorresponding to the shaped of a portion interposed between a pluralityof gas discharging holes, the coolant path is not necessarily shaped tobe concentric. For example, if the gas discharging holes 46 are arrangedin a lattice pattern, as shown in FIG. 31, there may be formed coolantpassages 250 a, 250 b in the form of straight passages becauserespective portions among the gas discharging holes 46 are also shapedin a lattice pattern. In the modification, the coolant passage may beformed in a “zigzag” pattern, spiral pattern or the other pattern. Note,reference numerals 251 a, 251 b designate coolant introducing parts,while numerals 252 a, 252 b designate coolant discharging parts,respectively. Further, the coolant passage of this embodiment is notlimited to that in the above “SFD” case. Thus, the coolant passage ofthis embodiment is applicable that in the normal film deposition processand also adoptable for the apparatus in the previous embodiment.

Next, the third embodiment of the present invention will be described.

This embodiment also relates to an apparatus for carrying out thetechnique “SFD” in the initial W-film forming process. In thisembodiment, however, the supply pathway of SiH₄-gas and WF₆-gas in theinitial W-film forming process is divided into respective pathways inorder to suppress a reaction between these gases in the shower head.

FIG. 32 is a sectional view showing the main body of a CVD apparatus ofthis embodiment. Basically, this apparatus is constructed similarly tothe CVD apparatus of FIG. 2 in the first embodiment and is differentfrom it in its gas supply mechanism only. Therefore, elements identicalto those of FIG. 2 are respectively indicated with the same referencenumerals to simplify the explanation.

A gas supply mechanism 260 includes a ClF₃-gas supply source 261 forsupplying ClF₃-gas as the cleaning gas, a WF₆-gas supply source 262 forsupplying WF₆-gas being a W-containing gas as the deposition material, afirst Ar-gas supply source 263 for supplying Ar as the carrier gas andthe purge gas, a SiH₄-gas supply source 264 for supplying SiH₄-gas asthe reduction gas, a second Ar-gas supply source 265, a H₂-gas supplysource 266 for supplying H₂-gas as the reduction gas, a third Ar-gassupply source 267 and a N₂-gas supply source 268.

A gas line 269 is connected to the ClF₃-gas supply source 261, a gasline 270 being connected to the WF₆-gas supply source 262, and a gasline 271 is connected to the first Ar-gas supply source 263. These gaslines 269, 270 are connected to the gas introducing port 43 of the gasintroducing part 23. The gas line 271 from the first Ar-gas supplysource 263 is connected to the gas line 270. Respective gases from thesegas supply sources 261, 262, 263 do flow from the gas introducing port43 to given pathways in the gas introducing part 23 and successivelyflow from the first gas passage 30 into the spatial part 22 a. Further,passing through the gas discharging holes 34 of the current plate 33 andreaching the spatial part 22 d, these gases are discharged from thefirst gas discharging holes 46.

A gas line 272 is connected to the SiH₄-gas supply source 264, while agas line 273 is connected to the second Ar-gas supply source 265. Thegas line 272 is connected to the gas introducing port 43 of the gasintroducing part 23. A blanch line 272 a blanching from the gas line 272is connected to the gas line 275 and further connected to the gasintroducing port 41 through the gas line 275. Additionally, a gas line273 from the second Ar-gas supply source 265 is connected to the gasline 272. Respective gases from these gas supply sources 264, 265 areintroduced into the spatial part 22 c through the second gas passage 44.Further, passing through the spatial part 22 b, these gases aredischarged from the second gas discharging holes 47.

Both of gas lines 274 and 275 are connected to the H₂-gas supply source266, while a gas line 276 is connected to the third Ar-gas supply source267. Further, a gas line 277 is connected to the N₂-gas supply source268. The gas line 274 is connected to the above gas introducing port 42,the gas line 275 being connected to the gas introducing port 41 of thegas introducing part 23, and both of the gas line 276 from the thirdAr-gas supply source 267 and the gas line 277 from the N₂-gas supplysource 268 are connected to the gas line 275. Respective gases fromthese gas supply sources 266, 267, 268 do flow from the gas introducingport 41 to designated routes in the gas introducing part 23 andsuccessively flow from the first gas passage 30 into the spatial part 22a. Further, passing through the gas discharging holes 34 of the currentplate 33 and reaching the spatial part 22 d, these gases are dischargedfrom the first gas discharging holes 46. On the other hand, H₂-gas thathas been supplied to the gas introducing part 42 through the gas line274 is discharged from the second gas discharging holes 47 formed in theouter peripheral part of the shower plate 35, allowing H₂-gas in theperiphery of the wafer to be supplemented in forming the main W-film.

Note, in these gas lines 269, 270, 271, 272, 273, 274, 275, 276 and 277,there are provided a mass-flow controller 278 and closing valves 279,280 in front and behind, for each line. Note, in the gas supplymechanism 260, the gas supply using the valves etc is controlled by acontrol unit 290.

Next, the operation of this embodiment will be described.

First, it is performed to mount a wafer W on the mount table 5, assimilar to the second embodiment. After claming the wafer W by the clampring 10, a high vacuum state is formed in the processing container 2 andfurther, the wafer W is heated to a predetermined temperature by thelamps 86 in the heating chamber 90.

During the film deposition process, as similar to the first and secondembodiments, it is performed to continuously supply Ar-gas as thecarrier gas from the Ar-gas supply source 53 at a predetermined flowrate and also performed to continue the formation of a vacuum by theexhaust unit. Note, as the carrier gas, Ar-gas may be replaced by theother inert gas, such as N₂-gas and He-gas.

Similarly to the second embodiment, according to this embodiment, theW-film formation is performed for a wafer having a film structure shownin e.g. FIG. 24, in accordance with e.g. a flow of FIG. 25. That is,after performing the initial W-film forming process ST1 by means of thetechnique “SFD”, the main W-film forming process ST2 is carried out.Note, similarly to the second embodiment, the repetition number of theinitial W-film forming process ST1 is not limited in particular.Additionally, the purging process may be accomplished by only allowingthe exhaust unit to evacuate without supplying the carrier gas.Alternatively, as occasion demands, such a purging process may beeliminated.

In the initial W-film forming process ST1, as typically shown in FIG.33A, the SiH₄-gas supply process S1 is accomplished by the followingflow of SiH₄-gas from the SiH₄-gas supply source 264 to the seconddischarging holes 47 in the periphery part of the shower head 22 via thegas line 272, the second gas passage 44, the spatial part 22 c of theshower head 22 and the spatial part 22 b, in order. Then, SiH₄-gas isdischarged from the second discharging holes 47. Note, SiH₄-gas iscarried by Ar-gas supplied from the second Ar-gas supply source 265 viathe gas line 273. While, as typically shown in FIG. 33B, the WF₆-gassupply process S2 is accomplished by the following flow of WF₆-gas fromthe WF₆-gas supply source 262 to the first discharging holes 46 via thegas line 270, the first gas passage 30, the spatial part 22 a of theshower head 22, the gas pass holes 34 in the current plate 33, and thespatial part 22 d, in order. Then, WF₆-gas is discharged from the firstdischarging holes 46. Note, WF₆-gas is carried by Ar-gas supplied fromthe first Ar-gas supply source 263 via the gas line 271. The purgingprocess S3 performed between these processes is to stop the supply ofSiH₄-gas and WF₆-gas and further supply Ar-gas while exhausting by theexhaust unit. Note, for convenience of understanding, the gasintroducing part 23 is eliminated in FIGS. 33A and 33B.

In the above way, although this embodiment differs from the secondembodiment with respect to the pathway of SiH₄-gas in the initial W-filmforming process ST1, the former is similar to the latter in terms of theother conditions, such as flow rate of gases and supplying periodthereof.

Also in this embodiment, by performing the supply of SiH₄-gas and thesupply of WF₆-gas alternately and repeatedly, the SiH₄-gas reducingreaction shown in the following formula (1) is generated. Consequently,as shown in FIG. 26, the initial W-film 237 functioning as thenucleation film is formed on the under barrier layer 236 uniformly, at ahigh step coverage. For instance, even if the aspect ratio of hole ismore than five, more preferably, ten, a uniform film can be produced ata high step coverage.

In supplying SiH₄-gas as the reduction gas and WF₆-gas as theW-containing gas alternately thereby forming an initial W-film, sinceSiH₄-gas and WF₆-gas are respectively supplied through the intermediaryof different gas routes separated from each other in the shower head 22,there is no contact between SiH₄-gas and WF₆-gas in the shower head 22.Therefore, without cooling down the shower head 22 to a temperaturebelow 30° C. and with the normal cooling, it is possible to prevent anundesired W-film from being formed in the shower head 22.

Note, the main W-film forming process ST2 succeeding to the initialW-film forming process ST1 is carried out in the same manner as the mostrecently mentioned embodiment while using WF₆-gas as the W-containinggas being a source gas and SiH₄-gas as the reduction gas.

Next, we describe another example of the shower head that allowsSiH₄-gas and WF₆-gas to be supplied through the gas routes separatedfrom each other in the shower head 22 in the initial W-film formingprocess ST1. FIG. 34 is a schematic sectional view showing anotherexample of the shower head of this embodiment and FIG. 35 is ahorizontal sectional view taken along a line F-F of FIG. 34. In FIGS. 34and 35, elements identical to those in FIG. 32 are indicated with thesame reference numerals, so that their explanations are simplified.

A shower head 322 includes a cylindrical shower base 339 whose outerperiphery is formed so as to fit the upper part of the lid 3, adisk-shaped introducing plate 329 arranged so as to cover the upper partof the shower base 339 and also provided, at the top center, with thegas introducing part 23, and a shower plate 335 attached to the lowerpart of the shower base 339.

The above gas introducing plate 329 is provided, at a center thereof,with a first gas introducing hole 330 for introducing a predeterminedgas into the shower head 322 through the gas introducing part 23. Aroundthe first gas introducing hole 330, a plurality of second gas passages344 are formed to introduce a different gas from the above in charge ofthe first gas passage into the shower head 122 through the gasintroducing part 23.

In the interior space of the shower head 322 surrounded by the showerbase 339, the gas introducing plate 329 and the shower plate 335, ahorizontal partition 331 in the form of a substantial circular ring ispositioned just below the gas introducing plate 329 horizontally. In theinner circumferential part of the horizontal partition 331, acylindrical projecting part 331 a is formed so as to gibbosite upwardly.This cylindrical gibbosity part 331 a is connected to the gasintroducing plate 329.

A cylindrical vertical partition 332 is arranged between the outerperiphery of the horizontal partition 331 and the shower plate 335. Inthe interior space of the partition 332, a current plate 333 is arrangedabove the shower plate 335 while positioning the plate's surfacehorizontally. This shower plate 335 is formed with a plurality of gaspass holes 334.

Therefore, the inside space of the shower head 322 is partitioned by aspatial part 322 a between the horizontal partition 331 and the currentplate 333, a spatial part 322 c between the gas introducing plate 329and the horizontal partition 331, an annular spatial part 322 betweenthe shower base 339 and the vertical partition 331 and a spatial part322 d between the current plate 333 and the shower plate 335. In theseparts, the spatial part 322 b is communicated with the spatial part 322c. Further, the first gas itroducing hole 330 of the gas introducingplate 329 is communicated with the spatial part 322 a, while the secondgas passage 344 is communicated with the spatial part 322 c. However,the spatial part 322 c is secluded from the spatial part 322 a by thehorizontal partition 331 and the gibbosity part 331 a. Again, thespatial part 322 b is secluded from the spatial part 322 a and also thespatial part 322 d by the vertical partition 332, respectively.

The above shower plate 335 is provided with a vertical double-layerstructure consisting of an upper plate 335 a and a lower plate 335 b. Asshown in FIG. 35, a spatial part 351 is formed in the upper plate 335throughout while leaving a plurality of column parts 353 vertically. Thevertical partition 332 is formed with a plurality of communication paths352 through which the spatial part 322 b communicates with the spatialpart 351. The plural column parts 353 are provided, at respectivecenters thereof and vertically, with gas flow holes 354 respectively.The gas flow holes 354 are adapted so as to lead a gas that has reachedthe spatial part 322 d, downwardly. In the lower plate 335 b, aplurality of first gas discharging holes 346 and a plurality of secondgas discharging holes 347 are formed vertically and also in a matrixpattern. The plural first gas discharging holes 346 communicate with theplural gas flow holes 354 of the upper plate 335 a, respectively. While,the plural second gas discharging holes 347 are arranged incorrespondence positions in the spatial part 351. Then, gas introducedfrom the first gas introducing hole 330 passes through the spatial part322 a, the gas pass holes 334, the spatial part 322 d and the gas flowholes 354 in order and is discharged from the first gas dischargingholes 346. While, gas introduced from the second gas passages 344reaches the spatial part 351 by way of the spatial parts 322 c, 322 andthe communication path 352, in order and is discharged from the secondgas discharging holes 347. Therefore, the shower head 322 constitutes a“matrix” shower that is equipped with the first and second gasdischarging holes 346 and 347 each discharging gases by way of differentgas supply pathways apart from each other, the pathways comprising: afirst gas supply pathway composed of the first gas passage 330, thespatial part 322 a, the gas pass holes 334 and the spatial part 322 d;and a second gas supply route composed of the second gas passages 344,the spatial parts 322 c, 322 d and the annular spatial part 351.

Also in the so-constructed shower head, since it allows WF₆-gas as theW-containing gas to be discharged from the first gas discharging holes346 through the first gas supply pathway and SiH₄-gas as the reductiongas to be discharged from the second gas discharging holes 347 throughthe second gas supply pathway perfectly separated from the first gassupply pathway, it is possible to prevent these gases from being reactedto each other in the shower head 322, whereby the adhesion of anundesired W-film to the interior of the shower head 322 can beprevented. Additionally, the matrix shower like this enables SiH₄-gas tobe supplied into the processing container 2 uniformly since the same gasflows through the spatial part 322 b and the communication path 352 andis diffused into the spatial part 351.

Note, in this embodiment, since SiH₄-gas as the reduction gas andWF₆-gas as the W-containing gas are discharged under theirmutually-isolated conditions due to the different supply pathways, thereis no need to always make the temperature of the shower head less than30° C. In view of preventing reaction by-product materials containingTiF_(x) from adhering to the shower head, the above temperature may bemore than 80° C., preferably, more than 100° C. Alternatively, if makingthe temperature of the shower plate less than 30° C. by use of theshower plate of FIGS. 21, 22, which is equipped with the coolantpassages in the gas-hole formation area, then it becomes possible toprevent film deposition onto the shower head certainly. Noted again,although SiH₄-gas as the reduction gas is used in forming the initialW-film, unlimitedly to this gas, there may be employed at least one kindof H₂-gas, SiH₄-gas, Si₂H₆-gas, SiCl₄-gas, SiH₂Cl₂-gas, SiHCl₃-gas,B₂H₆-gas and PH₄-gas. Further, without being limited to WF₆-gas only, anorganic W-containing gas may be employed as the W-containing gas.Furthermore, we have described the structure of a shower head byexamples of one structure having the gas passage for the central part ofthe shower head and the gas passage for the peripheral part and another“matrix” structure: nevertheless the structure of the shower head is notlimited to these structures only.

Without being limited to the above-mentioned embodiments, the presentinvention may be modified variously. For example, although the secondgas discharging holes 47 are formed vertically and inclined inwardly inthe above embodiments, they may be inclined outwardly. Additionally,although the present invention is applied to the CVD film deposition ofW in the above embodiments, not limited to this application, the presentinvention is also applicable to the CVD film deposition of Ti etc. thatemploys H₂-gas as similar to the film deposition of W. Further, thepresent invention is also applicable to an etching process. Stillfurther, the present invention can exhibit superior effects in theapplication to a gas processing using gas having a high diffusionvelocity, such as H₂-gas, and gas having a low diffusion velocity, suchas WF₆. However, unlimitedly to this application only, even whenprocessing an object with use of a single gas or if there is no greatdifference in diffusion velocity between gases on use, it is possible toprevent a reduction of gas concentration on the peripheral side of awafer W owing to the application of the present invention. Moreover, itshould be note that, unlimitedly to a wafer only, an object to beprocessed by the invention may be one of the other substrates.

As mentioned above, according to the present invention, theprocessing-gas discharging mechanism includes the first gas dischargingpart provided corresponding to a substrate to be processed mounted inthe mount table and the second gas discharging part arranged around thefirst gas discharging part independently to discharge the processing gasinto the circumference of the substrate to be processed mounted on themount table. Accordingly, by discharging the processing gas through thefirst gas discharging part and further discharging the processing gasfrom the second gas discharging part, it is possible to prevent theconcentration of the processing gas from being lowered in thecircumference of the substrate to be processed, accomplishing theapplication of a “uniform” gas processing in a plane to of the substrateto be processed.

Further, according to the present invention, since the gap layer isformed between the gas discharging part and the base part to function asa heat insulating layer, it is possible to suppress heat dispersion fromthe heater of the gas discharging part, allowing the gas dischargingpart to be heated with high efficiency.

Still further, according to the present invention, as the gasdischarging part is fastened to the base part so as to allow a relativedisplacement therebetween, even if the gas discharging part is heated bythe heater and expanded thermally, there is produced almost no strain inthe gas discharging part and also in the base part due to the relativedisplacement between the gas discharging part and the base part, wherebyit is possible to reduce the influence of thermal expansion on the gasdischarging part.

According to the present invention, in the apparatus to supply the firstprocessing gas and the second processing gas, which are required to keepthe temperature of the gas discharging part of the gas dischargingmechanism low, the coolant passage is arranged in the gas dischargingplate's area where the gas discharging holes are formed. Therefore, evenif the gas discharging mechanism is large-sized with the large-sizedsubstrate to be processed, it becomes possible to effectively cool thegas discharging part to a desired temperature without using any specialinstallation, such as ultra cold chiller and with a normal coolant, suchas cooling water.

Further, according to the present invention, when alternately supplyingthe first processing gas and the second processing gas in order to forma film, the processing container is supplied with the first processinggas and the second processing gas through the gas supply pathwaysseparated from each other in the gas discharging member. Therefore, asthe first processing gas does not come into contact with the secondprocessing gas in the gas discharging member, it becomes possible toprevent deposition of undesired film in the gas discharging memberwithout any special cooling.

1-66. (Canceled)
 67. A gas processing apparatus comprising: a processingcontainer for housing a substrate to be processed; a mount tablearranged in the processing container to mount the substrate to beprocessed thereon; a processing-gas discharging mechanism arranged in aposition opposing the substrate to be processed mounted on the mounttable to discharge a processing gas into the processing container; andexhausting means for exhausting an interior of the processing container,wherein the processing-gas discharging mechanism includes a first gasdischarging part provided corresponding to the substrate to be processedmounted in the mount table; and a second gas discharging part arrangedaround the first gas discharging part independently to discharge theprocessing gas into the periphery of the substrate to be processedmounted on the mount table.
 68. A gas processing apparatus for applyinga gas processing to a substrate to be processed while using a gascontaining a first processing gas of a relatively high diffusionvelocity and a second processing gas of a relatively low diffusionvelocity, the gas processing apparatus comprising: a processingcontainer for housing a substrate to be processed; a mount tablearranged in the processing container to mount the substrate to beprocessed thereon; a processing-gas discharging mechanism arranged in aposition opposing the substrate to be processed mounted on the mounttable to discharge a gas containing the first processing gas and thesecond processing gas into the processing container; and exhaustingmeans for exhausting an interior of the processing container, whereinthe processing-gas discharging mechanism includes a first gasdischarging part provided corresponding to the substrate to be processedmounted in the mount table to discharge the gas containing the firstprocessing gas and the second processing gas; and a second gasdischarging part arranged around the first gas discharging partindependently, to discharge the first processing gas into the peripheryof the substrate to be processed mounted on the mount table.
 69. A gasprocessing apparatus as claimed in claim 67 or claim 68, wherein theprocessing-gas discharging mechanism has a heater.
 70. A gas processingapparatus as claimed in claim 67, wherein the processing-gas dischargingmechanism includes a gas discharging plate having the first gasdischarging part and the second gas discharging part, and the first gasdischarging part and the second discharging part each have a pluralityof gas discharging holes formed in the gas discharging plate.
 71. A gasprocessing apparatus as claimed in claim 67 or claim 68, wherein theprocessing-gas discharging mechanism further includes a base part forsupporting the gas discharging plate and a gap layer between the gasdischarging plate and the base part.
 72. A gas processing apparatus asclaimed in claim 67 or claim 68, wherein the processing-gas dischargingmechanism includes cooling means for cooling the gas discharging plate,the cooling means having a coolant supply path arranged in the outerperipheral part of the processing-gas discharging mechanism to introducea coolant, a coolant discharging path arranged in the outer peripheralpart of the processing-gas discharging mechanism to discharge thecoolant and a coolant passage communicating the coolant supply path withthe coolant discharging path.
 73. A gas processing apparatus as claimedin claim 72, wherein the coolant passage is arranged in an area of thegas discharging plate where the gas discharging holes are formed.
 74. Agas processing apparatus as claimed in claim 73, wherein the coolantpassage is formed so as to correspond to the shape of a gas dischargingplate's part interposed among the plural gas discharging holes in thegas discharging plate's area where the gas discharging holes are formed.75. A gas processing apparatus as claimed in claim 73, wherein thecoolant passage is formed concentrically.
 76. A gas processing apparatusas claimed in claim 67 or claim 68, further comprising: a coolant flowpiping arranged both in upstream of the coolant passage arranged in theprocessing-gas discharging mechanism and in the downstream of thecoolant passage; a bypass piping connected, both in upstream of theprocessing-gas discharging mechanism and in the downstream, to thecoolant flow piping while bypassing the processing-gas dischargingmechanism; a pressure relief valve arranged on the downstream side ofthe coolant passage in the coolant flow piping; a group of valvesdefining a flowing pathway of the coolant; control means for controllingthe group of valves; and a heater for heating the processing-gasdischarging mechanism, wherein when cooling the processing-gasdischarging mechanism, the control means controls the group of valves soas to allow the coolant to flow into the coolant passage, when heatingthe processing-gas discharging mechanism, the control means operates theheater and further controls the group of valves so as to stop the inflowof the coolant into the coolant passage and allow the coolant to flowinto the bypass piping, and when lowering a temperature of theprocessing-gas discharging mechanism in its elevated condition intemperature, the control means controls the valves so as to allow thecoolant to flow into both of the coolant passage and the bypass piping.77. A gas processing apparatus as claimed in claim 70, wherein theplural gas discharging holes included in the second gas discharging partare arranged outside the periphery of the substrate to be processed onthe mount table.
 78. A gas processing apparatus as claimed in claim 77,wherein the plural gas discharging holes included in the second gasdischarging part are arranged perpendicularly to the substrate to beprocessed on the mount table.
 79. A gas processing apparatus as claimedin claim 77, wherein the plural gas discharging holes included in thesecond gas discharging part are arranged in the periphery of the firstgas discharging part, in one or more lines.
 80. A gas processingapparatus as claimed in claim 77, providing that the plural gasdischarging holes included in the second gas discharging part arearranged in the periphery of the first gas discharging part in two ormore lines, wherein the plural gas discharging holes are arranged so asto alternate with each other.
 81. A gas processing apparatus as claimedin claim 67, wherein the exhausting means includes a baffle plate forexhausting from the peripheral side of the substrate to be processed onthe mount table, an annular exhaust space arranged below the baffleplate and an exhaust hole in communication with the exhaust space, whichis arranged in a diagonal position of the processing container.
 82. Agas processing apparatus as claimed in claim 81, wherein a bottompartition wall is arranged in the exhaust space adjacent to the exhausthole.
 83. A gas processing method for applying a gas processing to asubstrate to be processed in a processing container while supplying aprocessing gas to the substrate, the gas processing method comprisingthe steps of: discharging the processing gas through a first gasdischarging part provided so as to oppose the substrate to be processed;and discharging the processing gas to the circumference of the substrateto be processed through a second gas discharging part provided aroundthe first gas discharging part independently, thereby performing the gasprocessing.
 84. A gas processing method as claimed in claim 83, whereingas containing the processing gas of a relatively low diffusion velocityis discharged from the first gas discharging part provided so as tooppose the substrate to be processed, and the processing gas of arelatively high diffusion velocity is discharged to the circumference ofthe substrate to be processed from the second gas discharging partprovided around the first gas discharging part independently, therebyperforming the gas processing.
 85. A gas processing method as claimed inclaim 84, wherein the processing gas containing WF₆-gas is dischargingfrom the first gas discharging part, while the processing gas containingH₂-gas is discharging from the second gas discharging part, therebyforming a film on the substrate to be processed.
 86. A gas processingmethod as claimed in claim 85, wherein the processing gas dischargedfrom the first gas discharging part contains H₂-gas, and the flow rateof H₂-gas from the second gas discharging part is 50% or more percent ofthe flow rate of H₂-gas from the first gas discharging part.
 87. A gasprocessing apparatus comprising: a processing container for housing asubstrate to be processed; a mount table arranged in the processingcontainer to mount the substrate to be processed thereon; aprocessing-gas discharging mechanism arranged in a position opposing thesubstrate to be processed mounted on the mount table to discharge aprocessing gas into the processing container; and exhausting means forexhausting an interior of the processing container, wherein theprocessing-gas discharging mechanism includes a gas discharging platehaving a discharging hole for discharging the gas; a base partsupporting the gas discharging part; a heater provided in the gasdischarging part; and a gap layer defined between the gas dischargingpart and the base part.
 88. A gas processing apparatus as claimed inclaim 87, wherein the gap layer has a fastening mechanism for fasteningthe gas discharging plate to the base part so as to allow a relativedisplacement therebetween.
 89. A gas processing apparatus as claimed inclaim 88, wherein the fastening mechanism includes a holding part forfixing the gas discharging plate to the base part and a moving partarranged on the opposite side of the holding part to allow a relativedisplacement between the gas discharging plate and the base part.
 90. Agas processing apparatus as claimed in claim 87, wherein theprocessing-gas discharging mechanism has a coolant passage.
 91. A gasprocessing apparatus as claimed in claim 90, further comprising: acoolant flow piping arranged both in upstream of the coolant passage andin the downstream; a bypass piping connected, both in upstream of theprocessing-gas discharging mechanism and in the downstream, to thecoolant flow piping while bypassing the processing-gas dischargingmechanism; a pressure relief valve arranged on the downstream side ofthe coolant passage in the coolant flow piping; a group of valvesdefining a flowing pathway of the coolant; control means for controllingthe group of valves; and a heater for heating the processing-gasdischarging mechanism, wherein when cooling the processing-gasdischarging mechanism, the control means controls the group of valves soas to allow the coolant to flow into the coolant passage, when heatingthe processing-gas discharging mechanism, the control means operates theheater and further controls the group of valves so as to stop the inflowof the coolant into the coolant passage and allow the coolant to flowinto the bypass piping, and when lowering a temperature of theprocessing-gas discharging mechanism in its elevated condition intemperature, the control means controls the group of valves so as toallow the coolant to flow into both of the coolant passage and thebypass piping.
 92. A gas processing apparatus as claimed in claim 87,wherein a spacer ring is arranged on the outer peripheral side of thegas discharging plate to fill up a space between the gas dischargingplate and a peripheral wall in the processing container.
 93. A gasprocessing apparatus as claimed in claim 87, wherein the heater isembedded in the outer peripheral part of a lower part of the gasdischarging plate.
 94. A gas processing apparatus as claimed in claim87, wherein a seal member is arranged in an inner peripheral partbetween the gas discharging plate and the base part.
 95. A gasprocessing apparatus as claimed in claim 88, wherein a member offluorocarbon resin is arranged between the fastening mechanism and thegas discharging plate in a manner that when the member is expandedthermally, the relative displacement between the fastening mechanism andthe gas discharging plate can be absorbed by slipping of the member. 96.A gas processing apparatus as claimed in claim 87, wherein theexhausting means includes a baffle plate for exhausting from theperipheral side of the substrate to be processed on the mount table, anannular exhaust space arranged below the baffle plate and an exhausthole in communication with the exhaust space, which is arranged in adiagonal position of the processing container.
 97. A gas processingapparatus as claimed in claim 96, wherein a bottom partition wall isarranged in the exhaust space proximity to the exhaust hole.